Monthly Archives: October 2016

Tantalum Carbide Nanoparticle

Tantalum Carbide Nanoparticle

Tantalum Carbide Nanoparticle: Transition metal carbides are in demand for the unique properties resembling with metal and ceramics constituents. These carbides have high hardness, high melting temperature, and high temperature strength. They have been used as hard constituents in metal matrix composites for high temperature applications and as coatings on cutting tools. Among these carbides tantalum carbide is very important and promising example for industrial applications.

Tantalum Carbide Nanoparticle

Carbide is a compound composed of carbon and a less electronegative element. The carbides of group IV (Ti, Zr, Hf) and group V (V, Nb, Ta) elements have metal-like properties, such as high thermal and electrical conductivity. They are opaque and have a metallic luster. Transition metal carbides are important materials because they possess some desired properties such as corrosion and wear resistance, electronic, magnetic and catalytic characteristics. They have extremely high melting points and are therefore referred to collectively as the “refractory carbides”.

Tantalum Carbide Nanoparticle (TaC) form a family of binary chemical compounds of tantalum and carbon with the empirical formula TaC, where x usually varies between 0.4 and 1. TaC is extremely hard, brittle, gold colored metalloid which is of considerable interest because of high melting point (4150 °C). It is refractory ceramic materials with metallic electrical Conductivity. The melting points of tantalum carbides peak at about 3880 °C depending on the purity and measurement conditions.

Tantalum carbide is frequently used in materials engineering due to its high corrosion resistance in aqueous solutions at temperatures up to 247 °C. The bonding between tantalum and carbon atoms in tantalum carbides is a complex mixture of ionic, metallic and covalent contributions, and because of the strong covalent component these carbides are very hard and brittle.

TaC has a micro hardness of 1800 kg/mm2 and an elastic modulus of 285 GPa, whereas the corresponding values for tantalum are 110 kg/mm2 and 186 GPa. Tantalum carbides have metallic electrical conductivity, both in terms of its magnitude and temperature dependence.

Properties of Tantalum Carbide Nanoparticle

Tantalum carbide (TaC) has high hardness, high melting point, high chemical stability, good resistance to chemical attack and thermal shock, and excellent oxidation resistance and corrosion resistance, which makes it very attractive for anti-ablation applications. It is found that the ablation mechanism of throat materials could be divided into three categories: sublimation, oxidation and mechanical abrasion. Addition of TaC into throat materials can effectively depress the oxidation reaction during the ablation process by means of forming tantalum oxides (TaO) to make up for the defects of materials and inhibit further oxidation damage.

On an industrial scale, tantalum carbide has primarily been produced by the carbothermal reduction of Ta2O5 with carbon due to the low cost of raw materials. It has been reported that tantalum carbides can be obtained by heating Ta2O5 at high temperature under high vacuum, and higher temperatures for long time. A fast and complete reaction takes place due to high temperature treatment of TaC, so it also causes coarsening of the carbide grains. The reduction of carbide size generally gives a significant improvement of the mechanical properties. The toughness of ceramics can be increased considerably without sacrificing the hardness by reducing the grain size. Tantalum carbide is added to some grades of cemented carbides to make hard carbide cutting tools which have a low coefficient of friction and a high resistance to mechanical shock.

Applications of Tantalum Carbide Nanoparticle (TaC)

They are suitable to cut a variety of materials such as gray cast iron, ductile nodular iron, austenitic stainless steel, nickel-base alloys, titanium alloys, aluminum, free-machining steels, plain carbon steels, alloy steels, and martensitic and ferrite stainless steels. Tantalum and molybdenum carbide coatings are used industrially for wear protection of steel moulds employed in injection cast molding of aluminum and aluminum alloys.

Tantalum Carbide Nanoparticle

Tantalum Carbide Nanoparticle

High speed steel tools for machining were coated with TaC by chemical vapor deposition (CVD), and were used in a high speed milling machine. TaC is desirable for market applications such applications as boost rocket motor nozzles that require high thermal-shock resistance. In the commercial sector, TaC has potential application as a material used for cutting tools and wear parts. Tantalum carbide has wide application in biomedical, corrosion, aerospace and electro technology.

TaC stands as a candidate material for next generation thermal heat protection, space aircrafts, automotive wear resistant liners, and propulsion-exposed components. Due to their optical, electronic and magnetic properties, tantalum carbides have been used for optical coatings, electrical contacts and diffusion barriers. Though tantalum carbide (TaC) has been proposed for use as wound filaments in the form of wires, it is prohibited due to the low strength of TaC wires. In the industrial world, it can be used in machining-tool materials to reduce the tendency of welding between steel chips and tool material.

Tin Oxide Nanoparticles Application


Contact Us for Tantalum Carbide
From us, you can easily purchase Tantalum Carbide Nanoparticle at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


Tantalum Nanopowder

Tantalum Nanopowder

Tantalum Nanopowder: Nanoparticles are currently being evaluated and used in many fields owing to their excellent diffusion and optical properties, ability to form suspensions and high surface area to volume ratio. Tantalum is highly conductive to heat and electricity and this property have made it the material of choice for electronic capacitors used in telecommunications and hand-held electronic equipment such as laptops and mobile phones.

Tantalum nanoparticles enhance the applications of the material due to their high surface area and ability to be dispersed in a printable ink. These nanoparticles should be stored in cool and dry room to prevent their dispersion performance from being affected by exposure to air.

Tantalum Nanopowder

Tantalum Nanopowder

Due to their peculiar structural characteristics and size effects, nanomaterials exhibit some novel physical and chemical properties which are different from those of the bulk materials and are of great interest both for theoretical study and for potential nanodevice applications. Today, features on the nanometer scale commonly determine the key physical properties of many materials.

Due to the high melting point of tantalum, at 2996 °C and boiling point at 5425 °C, respectively, the preparation of nano-tantalum by physical methods is very difficult. Many chemical methods were used to synthesize tantalum powder from TaCl5 or K2TaF7. The particle size of the tantalum particles prepared from these methods ranges from 1 µm to several hundred um.

Nanoscale Tantalum Nanopowder has been widely studied for a variety of applications. For example, superfine and pliable tantalum powders were needed to improve the quality or reduce package size of capacitors. Reduction in package size allows designers to add higher-capacitance-value parts to existing circuits or to use smaller package size to further miniaturize their circuits.

Properties of Tantalum nanoparticles:

Tantalum Nanopowder is a rare, shiny, gray, dense metal. It is highly ductile and can be drawn into a thin wire. Its chemical properties are very similar to those of niobium. Tantalum is highly corrosion resistant due to the formation of an oxide film. It is an excellent conductor of heat and electricity. The metal has a melting point exceeded only by tungsten and rhenium. Tantalum is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refectory metals are tungsten, molybdenum, rhenium and niobium. Tantalum is considered to be non-toxic.

Properties Tantalum Nanopowder
Chemical Symbol Ta
Molar Mass 180.94 g/mol
Melting point 2996 ° C
Boiling point 5425° C
Density 16.69 g/cm3
Electronic config. [Xe]4f 145d26s2

Tantalum Nanopowder is used in the electronics industry for capacitors and high power resistors. It is also used to make alloys to increase strength, ductility and corrosion resistance. The metal is used in dental and surgical instruments and implants, as it causes no immune response.

Applications of Tantalum Nanoparticles

The important application which benefited from the introduction of powder (particle) metallurgy is use of tantalum as bone implants. Porous materials have re-shaped the landscape of bone implants, as they allow for bone in growth and biological fixation, and eliminate implant loosening and related treatment failures. The unique bone-mimicking properties of porous tantalum enabled the use of tantalum as a material for bulk implants, and not only for coatings, as is the case with other porous metals.

Moreover, porous tantalum also facilitates the in growth of soft tissue, including the formation of blood vessels that were found to assemble on the surface and within the structure of the porous tantalum. Also, since tantalum is strongly radiopaque due its high atomic number, this property is widely employed for marking in orthopedics and in endovascular medical devices. Another important development was the production of nanoparticles based on tantalum. These particles have been shown to be superior to iodinated contrast agents for blood pool imaging applications due to their longer circulation time.

Their properties are similar to gold nanoparticles, but are far more cost-effective, and thus, well-positioned to replace gold in regenerative medicine for labeling and tracking of cell grafts through x-ray-based imaging. However, the amount of tantalum nanoparticles that can be taken up by stem cells is not enough to make individual cells visible in x-ray images. Thus, alternative strategies are needed, such as hydrogel or nanofiber scaffolds, which can be loaded with higher concentrations of nanoparticles, to increase the precision of cell deposition and allow tracking under x-ray guidance.

Tantalum Nanopowder


Contact Us for Tantalum Powder
From us, you can easily purchase Tantalum Nanopowder at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


Tin Oxide Dispersions

Tin Oxide Dispersions

Tin Oxide Dispersions: The dispersion is a system in which the particles are dispersed in a continuous phase of different composition or state. Nanopowder is the solid form of nanoparticles, which are usually, contains the nano sized agglomerate. These agglomerates can be re-dispersed using various methods like ultrasonication, stirring etc.

Tin Oxide Dispersion

Tin Oxide Dispersion

Tin oxide is a wide band gap n-type semiconductor with many potential applications such as catalysts for oxidation of organics, gas sensors, electrodes in solid-state ionic devices, molecular sieves, and solar cells due to its being chemically inert, mechanically hard, and thermally heat-resistant. The success in many of its technological applications depends on crystalline SnO2 with a uniform nanosized pore structure.

Tin oxide is used widely to control air pollution and to detect toxic or smelling gases at low levels in the air and in the field of domestic and industrial applications. As the size of the particle decreases, the surface to volume ratio increases, this increases the number of oxygen sites on the surfaces in these reducing gas species and the sensitivity of nanocrystalline tin oxide.

Tin Oxide Dispersions

As for most natural materials, the size of SnO2 dispersions particles varies within 1-80 nm of length and 10-100 nm of inner diameter, depending on the deposits. This material has an average diameter of 50 nm.

SnO2 can be synthesized using a variety of techniques such as sol-gel, hydrothermal method, precipitation, carbothermal reduction, and polymeric precursor. The hydrothermal method is one of the best methods to produce fine oxide powders due to its simplicity, efficiency, and environmental friendliness. It is known that well dispersed particles have larger surface areas and smaller particle sizes, which are desired to increase the reaction sites. One of the effective methods for obtaining well dispersed and homogeneous particles is to re-crystallize them under hydrothermal treatment.

Tin Oxide Dispersions

Chemically, the properties of Tin oxide dispersions are nearly similar to the tin oxide powder. When the powder is getting dispersed into any organic solvent to form dispersion, the sizes of particles become smaller. The morphology of this dispersion is spherical as shown in figure. The zeta size or average particle size of tin oxide dispersion is 20-80 nm. It is acidic in nature i.e. pH lies between 4-5. A wide range of organic solvents are used including DMF, Ethanol, methanol, IPA and water to form dispersions.

We foresee a great deal of fundamental research and many applications employing tin oxide dispersion in various sensing applications like in gas sensors, pressure sensors etc. Thin films of tin oxide dispersion are also used in the dye sensitive solar cells. It is expected that highly crystalline particles, with an average diameter of less than 10 nm, will sinter at lower temperatures, and thus, allow broader application to complex geometries, heat-sensitive materials, and flexible substrates. Also used as catalysts, energy-saving coatings and anti-static coatings, in the making of optoelectronic devices and resistors. SnO2 layers have been used as transparent and electrically conducting coatings on glass. These films have a high mechanical and chemical stability.

Tin Oxide Dispersions


Contact Us for Tin Oxide Dispersions
From us, you can easily purchase Tin Oxide Dispersions at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


Tin Oxide Nanoparticles Application

Tin Oxide Nanoparticles Application

Tin Oxide Nanoparticles Application: Nanostructure metal oxides have attracted a lot of attention due to their technological applications and outstanding properties. The magnetic, optical, catalytic and electronic properties of nanomaterials depend strongly on size, structure and shape of nanoparticles. Another reason for attraction of scientists’ attention towards nano size particles is that, they behave differently from bulk materials. With decreasing particle size the band structure of the semiconductors changes. The band gap increases and band edges splits into decrease energy levels.

Tin Oxide Nanoparticles Application

Tin Oxide Nanoparticles Application

Recent research, on tin oxide semiconductor has been growing due to the wide range of its applications including gas sensors, transistors, electrodes, liquid crystal displays, catalysts, photovoltaic devices, photo sensors, antistatic coating etc. Tin oxide is one of the most important materials due to its high degree of transparency in the visible spectrum, strong physical and chemical interaction with adsorbed species, low operating temperature and strong thermal stability in air up to 5000 °C. Tin occurs in two oxidation states +2 and +4, therefore two types of oxides are possible i.e. stannous oxide (SnO) and stannic oxide (SnO2). Among these two oxides, SnO2 is more stable than SnO.

SnO2 nanoparticles have been synthesized by varies methods like Sol Gel, Micro Wave technique, Solvo-thermal, Hydro thermal, Sonochemical, Mechanochemical, Co-precipitation etc. The highly pure and crystalline nanoparticles of SnO2 have been synthesized using Co-precipitation method. This Co-precipitation method is simple, inexpensive and does not require high temperature and pressure. Here the size and shape of the particle can be controlled by altering pH of the medium, concentration of the precursor and precipitating reagents. Impurities in the precipitate are easily eliminated by filtration and repeated washing.

After some time the particles undergo aggregation. The degree of aggregation depends on the nature of the particles and the conditions during their synthesis. To avoid aggregation of the particles and to reduce the size of the particles, some organic surfactants are used during the precipitation. Use of surfactants will help in tailoring the size and shape of the nanoparticles and to hinder the aggregation. Using Co -precipitation method and using surfactants, SnO2 nanoparticles can be synthesized with the size ranging between 5nm and 23nm.

Properties of Tin Oxide Nanoparticles

Properties Tin Nanoparticle
Molar Mass 150.71 g/mol
Melting point 1630 °C
Boiling point 1900 °C
Density 6.95 g/cm3
Electronic config Tin [Kr] 4d10 5s2 5p2
Oxygen [He] 2s2 2p4

Basically the structural properties of any material can be characterized by XRD i.e. X-ray diffraction. The structural identification of Tin oxide nanoparticles is carried out by XRD in the range of angle 2 θ between 20 ° to 70 °. SnO2 nanoparticles are crystalline in nature and the size is very small which is calculated to be 36 nm (approx).

Scanning electron microscope (SEM) is used for the morphological study of SnO2 Nanoparticles. Spherical morphology with a highly porous, foam-like structure can be observed by SEM. Optical absorption measurement was carried out on SnO2 nanoparticles. The optical absorption coefficient has been calculated in the wavelength range of 300 – 800 nm. The absorption edge is obtained at a shorter wavelength. The broadening of the absorption spectrum could be due to the quantum confinement of the nanoparticles. The SnO2 nanoparticles have good crystalline structure and show strong blue emission, promising for applications in optical devices. UV absorption spectrum of SnO2 nanoparticles shows it absorbance edge is observed at 315 nm.

The dielectric studies show the effects of temperature and frequency on the conduction phenomenon in nanostructured materials. Dielectric behavior can effectively be used to study the electrical properties of the grain boundaries. The dielectric properties of materials are mainly due to contributions from the electronic, ionic, dipolar and space charge polarizations. Among these, the electronic polarization, present in the optical range of frequencies form the most important contribution to the polycrystalline materials in bulk form. Space charge polarization arises from molecules having a permanent dipole moment that can change its orientation when an electric field is applied. The dielectric parameters, like the dielectric constant (εr) and dielectric loss are the basic electrical properties of the SnO2 nanoparticles. The measurement of the dielectric constant and loss as a function of frequency and different temperatures reveals the electrical processes that take place in SnO2 Nanoparticles.

Tin Oxide Nanoparticles Application

Because of the Magnetic properties of tin oxide nanoparticles are used in magnetic data storage and magnetic resonance imaging.

Tin oxide (SnO2) nanoparticles, as one of the most important semiconductor oxides, has been used as photo catalyst for photo degradation of organic compounds.

Also used as catalysts, energy-saving coatings and anti-static coatings, in the making of optoelectronic devices and resistors. SnO2 layers have been used as transparent and electrically conducting coatings on glass. These films have a high mechanical and chemical stability.

Due to the mechanical stability of the SnO2 they are used in hot end coatings on bottles. Tin oxide nanoparticles has very good transparent mirror properties, due to this property they are used as electrodes and anti-reflection coatings in solar cells, as heat shields in electronic devices, in thermal insulation, in solar head collectors, in photovoltaic cells, in double glazing lamps.

Tin oxide nanoparticles are widely used in sensing applications due to its semi conductor properties like in smoke sensors, humidity sensors, gas sensors etc. The transparent electrical conduction property of tin oxide nanoparticles are mostly used in transparent ovens and in liquid crystal displays.

Tin Oxide Nanoparticles Application


Contact Us for Tin Oxide Nanoparticles
From us, you can easily purchase Tin Oxide Nanoparticles Application at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


Tin Nanoparticle

TIN Nanoparticle

Tin Nanoparticle: Nanoparticles research is rapidly growing into an extensive research area. This is due to the fact that nanoparticles can be easily altered by varying their chemical environment, shape and size. One of the key benefits of nanoparticles is that their properties differ from bulk material of the same composition.

Tin Nanoparticle

Tin Nanoparticle

Tin  Nanoparticle is a malleable post-transition metal that is not easily oxidized in air. It can be coated onto other metals to prevent corrosion. Tin nanoparticles (Sn) have high surface activity, large specific surface area, good dispersion performance and uniform particle size. Tin nanoparticles dispersed in lubricating oil can be used as multi-purpose oil additives, which have the potential to reduce friction and wear in automobile engines.

Nanostructured materials exhibit many properties, such as grain size, large surface areas, homogeneity and highly reactive surfaces, that have attracted attention because of the various resulting applications and theoretical studies. The properties of nanostructured materials are determined not only by the cluster size but also by the manner in which they are organized. The way that nanoclusters form nanostructures depends not only on the separation and the properties of inter-cluster interaction but also on the preparation method used. To obtain metallic nanoparticles like tin nanoparticles and some oxides, many techniques have been used, such as sol-gel, pulsed laser deposition, mechanochemical, wet-chemical synthesis, chemical reduction method, chemical liquid deposition (CLD), electrochemical, thermal decomposition, microwave irradiation, metal vapor deposition, and sonochemical techniques.

Tin Nanoparticle

Tin Nanopowder

Tin Nanoparticle: are synthesized by chemical reduction method. This method is more suitable for the Sn nanoparticles synthesis because the chemical reduction can use a low temperature, resulting in a better control of thermal oxidation of Sn nanoparticles.

Properties Tin Nanoparticle
Chemical Symbol Sn
Molar Mass 118.69 g/mol
Melting point 2602 ° C
Boiling point 2602 ° C
Density 7.31 g/cm3
Electronic config [Kr]4d105s25p2

Tin Nanopowder , a member of group IV of the periodic table, has the unusually low melting point and the unusually high boiling point. This great liquid range makes it easy to form alloys of Sn without loss by vaporization. At room temperature and normal pressure, tin exists in two allotropes: One is nonmetallic α-Sn which is stable at temperature below 13.2 ◦C. The other is metallic β-Sn which exists between 13.2 ◦C to 161 ◦C. β-Sn slowly converts to α-Sn at temperature less than 13.2 ◦C. This transformation was known as “Tin disease” or “Tin pest”. When the temperature is above 13.2 ◦C, α-Sn can also slowly convert to β-Sn.

Tin Nanoparticles: Potential applications

Tin nanoparticles are considered to be non-toxic and are therefore used for food packaging, such as tin cans. Typically, tin has a low melting point and a readiness to form alloys with other metal such as lead and bismuth. It is an important material in solder alloys. It is also used in transparent ant-static films, Anti-microbial, antibiotics and anti-fungal agents. Tin nanoparticles are mostly used in Coatings, plastics, nanofibres, bandages and textiles.

Tin Nanoparticle

food-packaging

Tin Nanoparticle

Lithium Ion Battery

Nanosized tin particles possess distinct properties compared with the bulk tin which have stimulated considerable interest in scientific research and technological applications. It is known that lithium ion battery performance can be enhanced by incorporating tin nanoparticles in the anode electrode, owing to the increase in interfacial area and decrease in lithium ion transport path length. The melting point of tin can decrease dramatically with particle size reduction to several nanometers owing to its enhanced surface area to volume ratio. The decreased melting point of tin nanosolder is highly desirable for preventing damage to electronic devices, caused by high reflow temperatures. Moreover, the low melting point metal nanoparticles have also been considered as a catalyst for the growth of semiconductor nanowires via solution liquid solid (SLS) mechanism, which is where the interest of this research lies.

Tin Nanoparticle

Bandages and Textiles

Tin Nanoparticle

Anti-Static Films

Tin Nanoparticle


Contact Us for Tin Nanoparticles
From us, you can easily purchase Tin Nanoparticle at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


CNTs Dispersions

CNTs Dispersions

CNTs DISPERSIONS: The dispersion is a system in which the particles are dispersed in a continuous phase of different composition or state. Carbon nanotubes are the solid form of nanoparticles, which are usually, contains the micro sized agglomerate. These agglomerates can be re-dispersed using various methods like ultrasonication, stirring etc.

Carbon nanotubes (CNTs) have great potential to be used as drug or single-stranded DNA (ssDNA) delivery reagents due to its ability to either penetrate or endocytosed inside of the cells with relatively low or no toxicity. However, in order to use CNTs DISPERSIONS as delivery tool for drug molecules, CNTs DISPERSIONS need to be dispersed in any liquid solution.

CNTs DISPERSIONS

CNTs DISPERSIONS

Due to the tremendous optical, electrical, and mechanical properties of carbon nanotubes , it enjoy a preeminent status in the range of nanomaterials, finding wide range of applications in biosensors, composites , field emission devices , electronic components, probe tip, etc. Delocalization of π-electrons renders them conducting and alleviates adsorption of various chemical moieties via π–π stacking interaction. A high aspect ratio makes them prone to entanglement and bundling. Particularly, carbon nanotubes are bundled with strong van der Waals interaction energy of ca. 500 eV/μm of tube–tube contact. Such high interaction energy renders CNT dispersion a challenging task.

Currently two approaches are widely used in nanotube dispersion— the mechanical approach and the chemical approach. The mechanical approach includes ultrasonication and high-shear mixing. These processes are time-consuming and less efficient. As reported earlier ultrasonication can result in fragmentation of CNTs, in turn, decreasing their aspect ratio. Besides this, the stability of the dispersion is poor.

On the other hand, the chemical approach includes both covalent and noncovalent methods. Covalent methods involve functionalization with various chemical moieties to improve solubility in solvents. However aggressive chemical functionalization at high temperature creates defects at the nanotube surface, consequently altering the electrical properties of carbon nanotubes. In contrast, a noncovalent approach involves adsorption of the chemical moieties onto the nanotube surface, either via π–π stacking interaction such as in DNA, uncharged surfactants, etc., or through coulomb attraction in the case of charged chemical moieties. The noncovalent approach is superior in the sense that it does not alter the π-electron cloud of graphene, in turn preserving the electrical properties of carbon nanotubes.

The nature of dispersion problem for CNTs is rather different from other conventional fillers, such as spherical particles and carbon fibers, because CNTs are characteristic of small diameter in nanometer scale with high aspect ratio (>1000) and thus extremely large surface area. In addition, the commercialized CNTs are supplied in the form of heavily entangled bundles, resulting in inherent difficulties in dispersion.

Properties of CNTs DISPERSIONS

The chemical bonding of CNTs is composed entirely of sp2 carbon– carbon bonds. This bonding structure – stronger than the sp3 bonds found in diamond – provides CNTs with extremely high mechanical properties. It is well known that the mechanical properties of CNTs exceed those of any existing materials. Although there is no consensus on the exact mechanical properties of CNTs, theoretical and experimental results have shown unusual mechanical properties of CNTs with Young’s modulus as high as 1.2 TPa and tensile strength of 50–200 GPa. These make CNTs the strongest and stiffest materials on earth. In addition to the exceptional mechanical properties associated with CNTs, they also possess other useful physical properties and chemical properties.

Mechanical dispersion of CNTs

The basis of CNT dispersion methods are introduced here, which are as follows:

Ultrasonication is the act of applying ultrasound energy to agitate particles in a solution for various purposes. In the laboratory, it is usually achieved using an ultrasonic bath or an ultrasonic probe/ horn also known as a sonicator. It is the most frequently used method for nanoparticles dispersion. The principle of this technique is that when ultrasound propagates via a series of compression, attenuated waves are induced in the molecules of the medium through which it passes. The production of these shock waves promotes the ‘‘peeling off” of individual nanoparticles located at the outer part of the nanoparticles bundles, or agglomerates, and thus results in the separation of individualized nanoparticles from the bundles. Ultrasonication is an effective method to disperse CNTs in liquids having a low viscosity, such as water, acetone and ethanol. However, most polymers are either in a solid or viscous liquid state, which requires the polymer to be dissolved or diluted using a solvent to reduce the viscosity before CNTs DISPERSIONS.

Calendering process, The calendar, or commonly known as three roll mills, is a machine tool that employs the shear force created by rollers to mix, disperse or homogenize viscous materials. This method has also been used to disperse color pigments for cosmetics and lacquers. The general configuration of a calendering machine consists of three adjacent cylindrical rollers each of which runs at a different. The first and third rollers, called the feeding and apron rollers, rotate in the same direction while the center roller rotates in the opposite direction. The material to be mixed is fed into the hopper, where it is drawn between the feed and center rollers. When pre-dispersed, the material sticks to the bottom of the center roller, which transports it into the second gap. In this gap, the material is dispersed to the desired degree of fineness. Upon exiting, the material that remains on the center roller moves through the second nip between the center roller and apron roller, which subjects it to even higher shear force due to the higher speed of the apron roller. A knife blade then scrapes the processed material off the apron roller and transfers it to the apron. This milling cycle can be repeated several times to maximize dispersion.

Stirring is a common technique to disperse particles in liquid systems and can be used as well to disperse CNTs DISPERSIONS in a polymer matrix. Size and shape of the propeller and the mixing speed control the dispersion results. After intensive stirring of CNTs in polymer matrix, a relatively fine dispersion can be achieved. MWCNTs can be dispersed more easily than SWCNTs by employing this technique, although the MWCNTs tend to agglomerate. This experimentally observed behavior is mainly caused by frictional contacts and elastic interlocking mechanisms. Other parameters, like sliding forces and weak attractive forces have only little effect on this tendency during stir; however, the agglomeration becomes spontaneous under static conduction. For some thermosetting polymers, such as epoxy, obvious CNT re-agglomerations were observed after several hours of curing reaction. In case of severely agglomerated CNTs, higher shear forces are needed to achieve a fine dispersion in the polymer matrix, this can be accomplished by employing high speed shear mixer at a speed up to 10,000 rpm.

Applications of CNTs

CNTs DISPERSIONS can be used as a flame-retardant additive to plastics; this effect is mainly attributed to changes in rheology by nanotube loading. These nanotube additives are commercially attractive as a replacement for halogenated flame retardants, which have restricted use because of environmental regulations. Some other commercial applications of CNTs dispersions are:

Coatings and Films

Leveraging CNTs DISPERSIONS, functionalization, and large-area deposition techniques, CNTs are emerging as a multifunctional coating material. For example, MWNT-containing paints reduce biofouling of ship hulls by discouraging attachment of algae and barnacles. They are a possible alternative to environmentally hazardous biocide-containing paints. Incorporation of CNTs in anticorrosion coatings for metals can enhance coating stiffness and strength while providing an electric pathway for cathodic protection. Widespread development continues on CNT based transparent conducting films as an alternative to indium tin oxide (ITO). A concern is that ITO is becoming more expensive because of the scarcity of indium, compounded by growing demand for displays, touch-screen devices, and photovoltaic’s. Besides cost, the flexibility of CNT transparent conductors is a major advantage over brittle ITO coatings for flexible displays. Further, transparent CNT conductors can be deposited from solution (e.g., slot-die coating, ultrasonic spraying) and patterned by cost-effective non lithographic methods (e.g., screen printing, micro plotting).

Energy Storage and Environment

CNTs DISPERSIONS are widely used in lithium ion batteries for notebook computers and mobile phones, marking a major commercial success. In these batteries, small amounts of MWNT powder are blended with active materials and a polymer binder, such as 1 wt % CNT loading in LiCoO2 cathodes and graphite anodes. CNTs provide increased electrical connectivity and mechanical integrity, which enhances rate capability and cycle life. Many publications report gravimetric energy storage and power densities for unpackaged batteries and super capacitors, where normalization is with respect to the weight of active electrode materials. The frequent use of low areal densities for active materials makes it difficult to assess how such gravimetric performance metrics relate to those for packaged cells, where high areal energy storage and power densities are needed for realizing high performance based on total cell weight or volume.

Biotechnology

Ongoing interest in CNTs as components of biosensors and medical devices is motivated by the dimensional and chemical compatibility of CNTs DISPERSIONS with biomolecules, such as DNA and proteins. At the same time, CNTs enable fluorescent and photo acoustic imaging, as well as localized heating using near-infrared radiation. SWNT biosensors can exhibit large changes in electrical impedance and optical properties in response to the surrounding environment, which is typically modulated by adsorption of a target on the CNT surface. Low detection limits and high selectivity require engineering the CNT surface (e.g., functional groups and coatings) and appropriate sensor design (e.g., field effects, capacitance, Raman spectral shifts, and photoluminescence).

CNTs DISPERSIONS


Contact Us for CNTs DISPERSIONS
From us, you can easily purchase CNTs DISPERSIONS at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


Silicon Nanoparticle

SILICON NANOPARTICLE

With the rapid development of nanoscience and nanotechnology in multidisciplinary fields, nanomaterials have attracted extensive attention. Heavy-metal-free nanoscale silicon has been investigated in depth for its unparalleled physical and chemical properties such as the feasibility for surface functionalization, size-dependent tunable multicolor light emission, stability against photo bleaching and intriguingly, favorable nontoxicity. The applications of Si nanoparticles (NPs) to energy source, electronic, sensor, catalysis and biomedical purposes.

Silicon Nanoparticle

Silicon Nanoparticle

Silicon Nanoparticle is a key material for microelectronics industry. In contrast to its extensive use in electronic device, bulk silicon has limited optoelectronic application due to indirect nature of its band gap. However, the up growth of nanotechnology has triggered many possible avenues for the applications of nanostructured silicon.

Silicon Nanoparticle

Silicon Nanopowder

Unlike other semiconductors, silicon is an indirect band gap material and manifests remarkable changes in optical and electronic properties when its size approximates to the bulk Bohr radius (4 nm for silicon). By increasing the radiative recombination probability through band-gap transitions instead of phonon-assisted indirect band-gap transitions, the intensity of photoluminescence (PL) can be greatly enhanced. Though until now there has been no consensus on the origin of these amazing characteristics of silicon nanocrystals, and many researchers confirm that these particular properties mostly derive from the combination of quantum confinement and surface states.

Silicon Nanoparticle

SEM image of Si NPs

The size-dependent phenomenon and other excellent properties, the morphologies and dimensions of Si nanocrystals must be well controlled either by synthetic approaches or subsequent analytical size-selected methods. The morphologies and sizes have been successfully regulated particularly in many narrow band gap II–VI, IV–VI, III–V semiconductor nanoparticles especially cadmium selenide (CdSe) quantum dots (QDs).

In spite of showing high photoluminescence (PL) efficiency, the surface oxidation of silicon nanoparticles (Si NPs) inhibits it from commercial applications. It has been observed that the air oxidation of hydrogen terminated Si-NPs decreases their PL intensity and causes a blue shift in their emission spectrum. Additionally, printed electronics based on nanosized silicon is also still a challenge due to the insulating oxide. The electrical properties of crystalline and amorphous Si-NPs have been studied and the effect of doping on the electrical properties of Si-NPs has also been investigated.

As the surface chemistry is also expected to strongly influence the electrical transport between Si-NPs and therefore the electrical properties of Si-NP ensembles, the conductivity of pellets consisting of Si-NPs was measured using impedance spectroscopy. The surface oxide of Si-NPs was removed by etching them with HF acid. The freshly etched Si-NPs showed much higher conductivity compared to as-prepared samples. The surface functionalization of freshly etched Si-NPs slightly decreases their conductivity.

Properties of Silicon nanoparticles

Color of the photoluminescence (PL)

In general, Silicon Nanoparticle prepared by gas-phase or by electrochemical methods show orange-red luminescence, whereas those produced by liquid-phase synthesis often emit blue light despite sometimes being of similar size. The classic signature of quantum confinement is the observation of size-dependent optical absorption or PL.

Silicon Nanoparticle , in bulk, has an indirect gap at 1.1 eV which is expected to be size-dependent and a direct gap at 3.4 eV which is not expected to be strongly size-dependent. The absorbance above the 1.1 eV threshold is weak and unstructured, therefore size-dependent PL measurements have been crucial. Using a pulsed CO2 laser to pyrolyze silane in a gas flow reactor and a molecular-beam chopper synchronized to the laser, were able to separate Si nanoparticles by size and demonstrate clearly the blue-shift of the luminescence peak with particle diameter. The smaller particles emitted lower photon energies than expected: this is thought to be due to traces of oxide which was shown in literature to introduce a level in the gap that limits the maximum observed PL energy to about 2.1 eV.

Typically Silicon Nanoparticle which emit red light do so via dipole-forbidden transitions with microsecond or longer lifetimes whereas the blue-emitting particles show nanosecond lifetimes typical of dipole-allowed transitions. Which type of particle is better depends the particular application: clearly red-emitters are more suitable if auto fluorescence is the major problem, but in some applications they may suffer from slow radiative recombination. In bulk Si, the band gap at 1.1 eV is indirect and emission of light is slow because simultaneous emission/ absorption of a lattice vibration (phonon) is necessary to conserve crystal momentum and nonradioactive processes dominate.

Electronic properties

PL properties of Silicon Nanoparticle are primarily due to the quantum confinement effect caused by the restricted size at the nanoscale. The existing quantum confinement model is closely related to the size-dependent band gap which is also one of the major characteristics of electronic nature. According to the research, after synthesizing Si NPs with a fair size range from 1–5 nm, they found that the valence band (VB) edges of the Si nanocrystals shifted down by 0.5 eV with respect to vacuum level, owing to electronic structure changes caused by quantum confinement. Moreover, the conduction band (CB) shift was measured as a function of the VB band shift which is quantitatively equal to twice the former. They confirmed the inverse relation between particle size instead of geometric shape and the size of the band shift.

Optical performance

Due to the low PL quantum yield (QY) of amorphous Si NPs, which is less than 2%, most researches focused on the size-dependent and efficient PL of Si nanocrystals. The special optical properties, including bright emission, photo-stability, size-dependent and wavelength-tunable luminescence, and long fluorescence lifetime make them suitable for many applications.

Applications of Silicon nanoparticles

As a stable solid support for such molecules or biomolecular conjugates they have opened the door to applications in sensors, drug delivery system, and smart materials. Silica nanoparticles can be used as building blocks in layered architecture of proteins on electrodes. It can be expected that the particle size and the surface charge of the used silica nanoparticles play a key role in modulating the properties of such multilayer architectures.

Silicon nanoparticles in Electronics

Silicon Nanoparticle is a commonly used as a semiconductor in electronics: devices such as transistors, printed circuit boards and integrated circuits make use of silicon’s properties to achieve maximum performance. Insulating material is defined by the fact that it has no free electrons—a semiconductor is an insulator that can easily be transformed into a conductor. The number of free electrons a material possesses will influence how well it can conduct electricity. Silicon has a low energy difference between its valence band (the layer of electrons that holds the substance together) and its conduction band (the layer of electrons where sufficient energy enables them to roam freely). This low energy difference means it is relatively simple to move electrons from the valence band into the conduction band, thus turning silicon into a semiconductor. A change in temperature is often enough to change the electrons’ behavior, creating pure, slightly conductive silicon.

Silicon Nanoparticle

Electronics

In order for silicon to function as a semiconductor in a range of electronics applications, the material is typically doped (a small impurity is added) to enable electrons to be released without drastically altering temperature. Although there are numerous kinds of silicon semiconductor materials, two the most commonly used materials in electronics applications include N type material and P type material. N-type material is created by introducing an impurity to silicon that has one more electron per atom than silicon does; as a result, there are a greater number of free electrons, and the silicon assumes a negative charge (because electrons are negatively charged). P-type material is created by adding an element whose atoms have one less electron than silicon; the result is a positively charged material. Many devices use P and N type silicon as as a reliable semiconductor for voltage.

Light-emitting applications

For light-emitting applications using Si NPs, most of them rely on their robust electroluminescence (EL) potential. The realization of this application demonstrated that through optimizing the confinement of holes and electrons of the nanocrystals layer, the semiconductor material can also be used in this field. Monodispersed size-separated silicon nanoparticles, multicolor silicon-based light-emission diodes (Si LEDs), featuring long-term stable EL as well as widely tunable colors ranging from deep red to orange–yellow, can be achieved. The Si NPs proved to play a pivotal role since the emission characteristic substantially originates from it through the comparison between EL and PL spectra. Moreover, the increasing external quantum efficiency (EQE) is partially determined by the reduced thickness of the Si NPs layer and the high wavelength emission of Si nanocrystals.

Silicon Nanoparticle

Light emitting diode

Energy and Electronics

Si NPs exhibit fascinating electronic and optical properties compared with bulk silicon and have been investigated in depth for photovoltaic applications. For lithium ion battery applications, silicon formulations such as silicon nanowires, silicon nanotubes and micro porous silicon nanoparticles have been widely investigated to overcome the disappointing shortcomings of previous silicon anodes. Despite the change in nanostructure, researchers have ceaselessly been searching for novel candidate anode materials featuring higher Li-ion storage and stronger rechargeable capability to serve as substitutes for low charge-stored carbon based anodes.

Silicon Nanoparticle


Contact Us for Silicon Nanoparticle
From us, you can easily purchase Silicon Nanoparticle at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.

Multi Walled Carbon Nanotubes

MULTI WALLED CARBON NANOTUBES

Carbon nanotubes (CNTs) describe a family of nanomaterials made up entirely of carbon. In this family, multi-walled carbon nanotubes (MWCNTs) are of special interest for the industry. These can be considered as a collection of concentric SWNTs with different diameters, lengths and properties. Structurally MWCNTs consist of multiple layers of graphite superimposed and rolled in on them to form a tubular shape. The distance between each layer is approximately 0.34 nm, slightly larger than the interlayer distance of graphite sheets and the layers are coupled to each other through van der Waals forces.

Multi Walled Carbon Nanotubes

Multi Walled Carbon Nanotubes

High aspect ratio, large surface area multiwall carbon nanotubes (MWCNTs) have the potential as Isotropically Conductive Adhesive (ICA) filler particles to reach the percolation threshold with small volume fraction loading. The MWCNT used in the present study have aspect ratios of 2500:1. MWCNT are electrically conductive independent of synthesis method and have extremely high strength to weight ratio offering the potential to improve the stiffness of the polymer matrix. The unique mechanical and electronic properties of multiwall nanotubes are proving to be a rich source of new physics and could also lead to new applications in materials and devices. CNTs can be created by either catalytic, arc discharge or laser-ablation methods.

Multi Walled Carbon Nanotubes

Multi Walled Carbon Nanotubes

There are two models that can be used to describe the structures of multi-walled nanotubes. In the Russian Doll model, sheets of graphite are arranged in concentric cylinders, e.g. a (0, 8) single-walled nanotube (SWNT) within a larger (0, 17) single-walled nanotube. In the Parchment model, a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled newspaper. The interlayer distance in multi-walled nanotubes is close to the distance between graphene layers in graphite, approximately 3.4 Å.

Arc-discharge, laser ablation and chemical vapor decomposition are the three main methods for the synthesis of CNTs. In arc-discharge method, CNTs are synthesized through arc vaporization of two graphite rod placed end to end, namely anode electrode and cathode electrode. Laser ablation method involves the sublimation of graphite target and condensation of laser-vaporized carbon/metal mixtures to form CNTs. As for chemical vapor decomposition, it involves the catalytic decomposition of a carbon containing gas and nanotube growth on metal catalyst particles impregnated on a substrate. Arc-discharge and laser ablation are widely employed for the synthesis of SWCNTs due to the high process temperature of around 1,200°C, which favours SWCNTs formation. Chemical vapor decomposition is suited for mass production of MWCNTs as it is a simple and economic technique at lower process temperature from 500 to 1,000°C.

Properties of Multi Walled Carbon Nanotubes

MWCNTs have excellent properties and are being employed in a large number of commercial applications. The properties of MWCNTs are:

• Morphology: MWCNTs have a high aspect ratio with lengths typically more than 100 times the diameter, and in certain cases much higher. Their performance and application is based not just on aspect ratio, but also on the degree of entanglement and the straightness of the tubes, which in turn is a function of the both the degree and dimension of defects in the tubes.

• Electrical: MWCNTs are highly conductive when properly integrated into a composite structure. The noticeable thing is that the outer wall alone is conducting; the inner walls are not instrumental to conductivity.

Physical: Defect–free, individual, MWCNTs have an excellent tensile strength and when integrated into a composite, such as a thermoplastic or thermo set compounds, can significantly increase its strength.

Thermal: MWCNTs have a thermal stability more than 600 °C, based on the level of defects and to certain extent on the purity as residual catalyst in the product can also catalyze decomposition.

Chemical: MWCNTs are an allotrope of sp2 hybridized carbon similar to graphite and fullerenes and as such have high chemical stability. However, one can functionalize the nanotubes to enhance both the strength and dispersibility of composites.

Potential Applications Multi Walled Carbon Nanotubes

Because of their special physico-chemical properties, MWCNTs are expected to play a major role in numerous applications:

Multi Walled Carbon Nanotubes

Multi Walled Carbon Nanotubes

Current or short-term applications are often based on the use of MWCNTs as a superior replacement of electrically conductive carbon blacks. Much of the history of plastics over the last half century has been a replacement for metal. For structural applications, plastics have made tremendous headway. However where electrical conductivity is required, metals are still preferred to plastics. This deficiency can be overcome by upgrading plastics with conductive fillers such as carbon black and graphite fibers. However the loading required providing the necessary conductivity is typically high, and the structural properties of the resulting plastic parts are highly degraded. Due to their high conductivity, high aspect ratio, and natural tendency to form ropes, MWCNTs are ideal in providing inherently long conductive pathways even at ultra-low loadings. The lower loading of additive can offer several advantages such as better process ability or higher retention of the mechanical properties of the original polymer. This is why the use of carbon nanotubes for antistatic and conductive applications in polymers is already a commercial reality, growing in sectors such as electronics and the automotive industry. For these applications, carbon nanotubes can compete with additives such as highly conductive carbon black on a price performance basis.

Applications that exploit this behavior of CNTs include EMI/RFI (electromagnetic and radio frequency interference) shielding composites, electrostatic dissipation (ESD), antistatic materials and (even transparent) coatings. Concrete examples in the automotive industry are fuel systems components and fuel lines (connectors, pump parts etc), exterior body parts for electrostatic painting as well as, in the electronic industry, conveyor belts, manufacturing tools and equipments, wafer carriers, clean room equipments, etc.

The improvement of mechanical properties in epoxy-glass fiber or epoxy–carbon fiber composites already known from the sport industry can also be used in the construction of light weighted composites for wind power generators and in the aircraft industry. Other medium term applications may include electrical conductive inks for printable circuits, low cost RFID tags or antennas in cars.

In the longer term, Carbon Nanotubes may also play a role in the modification of existing textile materials using electrostatic self-assembly and atomic layer deposition techniques to create novel and customizable surfaces on conventional textile materials with emphasis on natural fibers. This opens the way to the development of smart and intelligent textiles that combine new innovative functions.

Multi Walled Carbon Nanotubes


Contact Us for Multi Walled Carbon Nanotubes
From us, you can easily purchase Multi Walled Carbon Nanotubes at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.