OXIDATION OF TIB2-CAB6 COMPOSITE-MATERIAL

Oxidation in air of TiB2, CaB6, and composite powder material based on titanium diboride containing 1-30 wt.% of CaB6 with programmed heatin g from room temperature to 1000-degrees-C is studied. It is determined that the pattern of oxidation for these materials is mainly governed by their phase composition. Oxidation of solid solutions differs sligh tly from oxidation of the original TaB2. Oxidation of two-phase materi als is markedly affected by the presence of CaB6 as a second phase. Ox idation of these composites above 740-degrees-C increases a little and it increases sharply above 900-degrees-C or higher when the scale for med on CaB6 loses its protective properties.