h-BN > w-BN phase transition under dynamic-static compression

Shock compression has been known to induce phase transitions in solids since 1956 . The synthesis of dense forms of BN is an application of this concept.' it presents considerable technological potential. Many investigations have been made on BN polymorphic transition under static and dynamic compression . In 1967, Adadurov, et al. obtained hexagonal BN (h-BN) transformed to wurtzite BN (w-BN) under shock compression (about 20 GPa). Akashi et al. performed shock compression in the range 60-200 GPa on w-BN and zinc blende (z-BN) and found w-BN -> z-BN phase transition around 100 GPa, w-BN -> graphite-like BN (g-BN) and z-BN -> g-BN above 100 GPa. The objective of this letter is to report results of the application of the dynamic-static compression (DSC) method developed by Batsanov to the phase transition of h-BN; the microhardness, X-ray analysis and microstructure are also discussed.