Chemical treatment of cubic boron nitride grinding powders to remove admixtures

The paper examines the chemical and thermochemical treatment of cubic boron nitride (cBN) grinding powders with solutions of mineral acids and alkalis (sodium and potassium hydroxides) with different concentrations. In addition, cBN grains are treated with a sodium hydroxide melt at 350 to 700°C for 1 h. It is established that treatment with solutions of mineral acids and alkalis with different concentrations, even for a long time, has no effect on the decomposition of cBN grains. The cBN grains decompose under the action of sodium hydroxide melt and release ammonia. With increasing treatment temperature, the decomposition of cBN grains is intensified.