Phase and structural transformations in sintering of wurtzite boron nitride in shock waves

For the first time there have been performed experiments on sintering in shock waves of wurtzite boron nitride powder. Powders BNw both without additions and with additions of BN(sph) of particle sizes from 28 to 40 Mm, as well as diamond Cdiam of the same fraction, have been subjected to a shock compression. Polycrystals 8 to 16 in dia. and 40 mm long have been obtained. Investigations were made into phase and structural transformations in the process of sintering: direct BNw&rarrBNsph, and reverse BNwBNgr, BNsph&rarrBNgr (here 'gr' stands for graphite-like). Maximum degree of phase transition BNwBNsph makes 40%. Polycrystal strength drops with an increase in BNgr content. The most strong polycrystals have been obtained on introducing over 50% BNsph into the mixture with up to 5% BNgr.