Oxidation resistance of B6O-materials with different additives

The oxidation resistance of B6O materials with and without Y2O3/Al2O3 additives and a typical cBN material were analysed in dry and wet air using TG measurements for up to 10 h and static experiments in a muffle furnace for up to 50 h. The results showed that the oxidation of the materials is sensitive to the composition of the atmosphere. In wet air with 17 vol.% H2O a weight loss was measured for all materials. In dry air a parabolic increase of the mass and a formation of a glassy surface layer were observed for the B6O materials whereas the cBN-material is characterized by the formation of a mostly crystalline layer. The oxidation resistance is the lowest for the pure B6O and the highest for the investigated cBN material.