ChroMiuM boride

Use

Chromium boride occurs as very hard crystallinepowder in several phases: the CrBorthorhombic crystal, the hexagonal crystalCr2B, and the tetragonal crystal Cr3B2. Chromiumboride parts produced by powder metallurgyhave a specific gravity of 6.20 to 7.31,with a Rockwell A hardness of 77 to 88. Theyhave good resistance to oxidation at high temperatures,are stable to strong acids, and havehigh heat-shock resistance up to 1316°C. Thetransverse rupture strength is from 552 to 931MPa. CrB is used for oil-well drilling. A sinteredmaterial, used for gas-turbine blades, contains85% CrB with 15% nickel binder. It hasa Rockwell A hardness of 87 and a transverserupture strength of 848 MPa.