can't read?
Zirconium diboride (ZrB2) is a highly covalent refractory ceramic material with a hexagonal crystal structure. ZrB2 is an ultra high temperature ceramic (UHTC) with a melting point of 3246 °C.
Z 5936 (OTTO) Zirconium diboride, 99.5% Cas 12045-64-6 - used as an aerospace refractory, in cutting tools, and to protect thermocouple tubes.