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Zirconium diboride Nano Powder (ZrB2) is a highly covalent refractory ceramic material with a hexagonal crystal structure. ZrB2 is an ultra-high temperature ceramic with a melting point of 3246 °C. This along with its relatively low density of ~6.09 g/cm3 (measured density may be higher due to hafnium impurities) and good high-temperature strength makes it a candidate for high-temperature aerospace applications such as hypersonic flight or rocket propulsion systems.
It is an unusual ceramic, having relatively high thermal and electrical conductivities, properties it shares with isostructural titanium diboride and hafnium diboride. ZrB2 parts are usually hot pressed (pressure applied to the heated powder) and then machined to shape.
Sintering of ZrB2 is hindered by the material’s covalent nature and presence of surface oxides which increase grain coarsening before densification during sintering. Pressureless sintering of ZrB2 is possible with sintering additives such as boron carbide and carbon which react with the surface oxides to increase the driving force for sintering but mechanical properties are degraded compared to hot-pressed he extremely rapid heating rates can result in incomplete reactions between Zr and B, the formation of stable oxides of Zr, and the retention of porosity.
Stoichiometric reactions have also been carried out by reaction of attrition milled wearing materials by grinding Zr and B powder and then hot pressing at 600 °C for 6 h, and nanoscale particles have been obtained by reacting attrition milled Zr and B precursor crystallites 10 nm in size.
The reduction of ZrO2 and HfO2 to their respective diborides can also be achieved via metallothermic reduction. Inexpensive precursor materials are used and reacted according to the reaction.
Storage Conditions:
Airtight sealed, avoid light and keep dry at room temperature.
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