| 摘要 |
<p>Composition contng. B and N, pref. as hexagonal BN, and an additive for converting hexagonal to cubic BN are exposed to raised temp. and pressure, pref. >=50000 (esp. 50000-110000) atm. and temps. >=1200 degrees (pref. 1200-2000 degrees C.). Pref. catalysts consist of alkali(ne earth) metal, Pb, Sb and/or Sn or alloy of several of these metals, or of metal with non-catalysing material, but more pref. of Mg or Ca, or pref. nitride(s) of these metal(s) opt. mixed with metal(s). Cubic BN produced has hardness equal to that of diamond, is stable at 2000 degrees C. and can be used for polishing diamonds.</p> |
