Ultra High Temperature Ceramics

Zirconium Carbide Nanopowder: Ultra-High Temperature Ceramics are a family of compounds that display a unique set of properties, including extremely high melting temperatures (> 3000°C), high hardness, and good chemical stability and strength at high temperatures. Structural materials for use in high-temperature oxidizing environments are presently limited mostly to SiC, Si3N4, oxide ceramics, and composites of these materials.

Zirconium Carbide Nanopowder: UHTC materials are typically considered to be the carbides, nitrides, and borides of the transition metals, but the Group IV-V compounds (Ti, Zr, Hf, Ta) due to the superior melting temperatures and formation of stable high-melting temperature oxides. The combination of properties make these materials potential candidates for a variety of hightemperature structural applications, including engines, hypersonic vehicles, plasma arc electrodes, cutting tools, furnace elements, and high temperature shielding.

Zirconium Carbide Nanopowder: UHTCs all exhibit strong covalent bonding which gives them structural stability at high temperatures. Metal carbides are brittle due to the strong bonds that exist between carbon atoms. The largest class of carbides, including Hf, Zr, Ti and Ta carbides have high melting points due to covalent carbon networks although carbon vacancies often exist in these materials; indeed, HfC has one of the highest melting points of any material. Nitrides such as ZrN and HfN have similarly strong covalent bonds but their refractory nature makes them especially difficult to synthesize and process.

Zirconium Carbide Nanopowder: Boride ceramics offer an unusual combination of ceramic-like properties including high melting temperature (>3000°C), elastic modulus (~500 GPa), and hardness (>20 GPa) with metallic characteristics such as high electrical conductivity (~107 S/m) and thermal conductivity (60-120 W/m•K). This combination of properties makes UHTCs attractive for applications such as the leading edges of hypersonic aerospace vehicles and atmospheric re-entry vehicles, which require materials to retain their shape at temperatures in excess of 2000°C.

Zirconium Carbide Nanopowder: The development of ultra-high temperature ceramics for aerospace applications continues around the globe. Development is likely to be driven by “market pull” based on applications where performance requirements necessitate the use of ceramics due to some combination of temperature requirements, weight savings compared to heavier refractory metals, or use of simpler passive designs as opposed to more complex actively cooled components.