SYNTHESIS OF cBN UNDER DIFFERENT CONDITIONS OF CRYSTALLIZATION IN THE PRESENCE OF MICROPOWDERS cBN AS SEEDS

Abstract

The process of synthesis of cubic boron nitride (cBN) in high-pressure apparatuses with a reaction volume of 5,7 and 22 cm³ at a crystallization time of 60 and 420 s from a reaction mixture containing cBN micropowders of KM0,5/0, KM3/1 and KM5/3 grades as seeds (additional crystallization centers). The effect of grain size and the content of seeds in the reaction mixture at different times of cBN crystallization on the fractional composition of the synthesis product has been established. It is shown that the use of seeds increases the total content of micropowders in the synthesis product from 35–55 (without the use of seeds) to 70–75 wt. % both at a synthesis time of 60 and 240 s.