| 摘要 |
PURPOSE:To produce a sintered material having good thermal stability and electrical insulation from a commercially available boron nitride powder using a normal-pressure sintering process without using an oxide-based sintering assistant. CONSTITUTION:A powdery mixture produced by adding 0.9-10wt.% of boron carbide to boron nitride is formed, heated in an inert atmosphere (e.g. argon) or in vacuum up to 1600 deg.C and baked in a nitriding atmosphere at 1600-2100 deg.C. The oxide layer on the surface of the baron nitride powder is removed by reduction to improve the activity of the powder surface and the sinterability of the boron nitride powder. The bond between baron nitride particles is reinforced by the conversion of a part of the added B4C into boron nitride. |
