Abstract: The effect of K2O, Na2O and MgO on the corrosion properties of cubic boron nitride (CBN) and the reaction mechanism at high temperature were studied in this work. The results showed that when the CBN powders were heated in air atmosphere at 1200 ℃ for 1h, 6.36% of mass was lost and the single particle compressive strength was reduced from 5.94kg to 5.01kg. when CBN particles were mixed with K2O, Na2O, MgO respectively in the same molar ratio of 2:1 and heated in the atmosphere at 1200 ℃ for 1h, the mass loss of CBN was 29.9%, 25.2%, 18.7%, and the strength was reduced to 2.37kg, 2.84kg, 3.00kg correspondingly. The smaller the electro-negativity of metal element in the metal oxides, the bigger the mass loss of cubic boron nitride. There were many cracks on the surface of CBN, which resulted in the decreased strength of CBN and showed anisotropic oxidation on the surface.

Keywords: metal oxides     cubic boron nitride     corrosion mechanism