Home» Colloidal Silica (Silicon Dioxide Nanoparticles Dispersion)
Colloidal Silica is suspensions of silicon dioxide nanoparticles in water or various organic solvents such as ethanol or mineral oil. Nanoshel manufactures oxide nanopowders and nanoparticles with typical particle sizes ranging from 10 to 200nm and in coated and surface functionalized forms.
Nanoparticles have some special properties in optical, electric, thermal, and magnetic aspects. SiO2 is not only an important kind of semi conductive material but also used as the filler of plastic, rubber, coating and gooey because of its good properties of heat-resistance, weather ability and chemical stability. At present there are many preparation methods, but most of them concentrate on preparing SiO2 nanoparticles in solid state or dispersed in organic solvent. These methods are suitable for preparing the polymer-base composite material but difficult to prepare SiO2 nanoparticles/polymer emulsion coating or adhesive because nanoparticles are not easy to disperse uniformly in water system because of their strong hydrophilic properties.
SiO2 nanoparticles dispersed in water can be prepared from silicon by the way of "formation in situ" and "surface-modification in situ ". This kind of preparation method would be widely adopted because of being simple and convenient and cheap in price and effectively resolving dispersion stability of SiO2 nanoparticles in water.
Silicon Dioxide Dispersion
The chemical and physical characteristics of the different types of amorphous silicon dioxide dispersions contribute to the versatility of these compounds in a variety of commercial applications. Traditionally, silica has had a broad spectrum of product usage including such areas as viscosity control agents in inks, paints, corrosion-resistant coatings, etc. and as excipients in pharmaceuticals and cosmetics. In the food industry, the most important application has been as an anticaking agent in powdered mixes, seasonings, and coffee whiteners. However, amorphous silica has multifunctional properties that would allow it to act as a viscosity control agent, emulsion stabilizer, suspension and dispersion agent, desiccant, etc. The utilization of silica’s in these potential applications, however, has not been undertaken, partially because of the limited knowledge of their physiochemical interactions with other food components and partially due to their controversial status from a toxicological point of view.
Silica oxide dispersions are common additive in food production, where it is used primarily as a flow agent in powdered foods, or to absorb water in hygroscopic applications. It is the primary component of diatomaceous earth. Colloidal silica is also used as a wine, beer, and juice fining agent. In pharmaceutical products, silica aids powder flow when tablets are formed.
In semiconductor and light-emitting-diode (LED) production, colloidal silica is a critical component for producing absolutely flat and uniform wafer surfaces. In both industries, colloidal silica performs equally well as a rough surface remover and final polishing additive, and eliminates the need for other surface preparation steps.
In chemical-mechanical planarization, colloidal silica is used to flatten out the irregularities in the films applied to the semiconductor substrates during integrated circuit fabrication. With colloidal silica, different substrates (e.g., silicon, aluminum and sapphire) can be polished to a surface roughness of nanometer, or if needed Angstrom level. In all cases, wafers can be polished to low-defect and ultra-flat surfaces.
Colloidal silica can be used as a binder in zinc-rich coatings to produce hard, durable, protective coatings that shield steel and prevent corrosion in construction environments. At the same time, colloidal silica is facilitating the conversion from Cr VI to Cr III in electroplating industries. For zinc-rich and shop-primer coatings, colloidal silica is an excellent binder for producing mechanically stronger coatings that possess excellent welding properties, as well as resist damage and corrosion. These protective coatings provide ideal protection for steel used in construction.
Paint filler (extender pigment), usually white or slightly colored, such as silicon dioxide dispersions, the refractive index is less than 1.7 of a class of pigments. It has a coating with basic physical and chemical properties of the pigment, but because of similar refractive index and film material, which is transparent in the coating, coloring power and do not have the ability to cover a coloring pigment, is an indispensable paint pigment. Since the vast majority of the filler from natural ore processing products, and its chemical stability, wear resistance, water resistance and other characteristics of a good, and inexpensive, play a role in skeleton in the paint. By increasing the thickness of the coating is filled to improve the mechanical properties of the coating, and can play durable, corrosion resistant, heat insulation, matting and so on. On the other hand it as a way of reducing the manufacturing cost of paint, using its low cost, the price is far lower than the color pigments; hiding under the premise of the film meet, appropriately added to supplement the extender pigment in paint color pigments should some volume.