| 摘要 |
PURPOSE:To improve mechanical strength of the subject sintered compact by using an amorphous BN obtained by vapor phase synthesis from a raw material containing N and B or a blend of the amorphous BN and cubic BN as a raw material and processing and heating the amorphous BN or the blend in a thermodynamically stable region of cubic BN. CONSTITUTION:About 550V voltage from electric source 13 is applied between tungsten electrode 9 and 10 in a pressure-reduced case of DC plasma jetting device and arc is generated to form a plasma jet 14 and a mixed gas consisting of 5vol.% B2H6, 5vol.% NH3, 60vol.% H2 and 30vol.% Ar is fed at a rate of about 20l/min from inlet 11 and 100% amorphous film (hereafter a-BN film) having <=0.01mum particle size is deposited at a rate of about 200mum/min on a substrate 12 using a Si wafer heated to about 700 deg.C. The Si wafer is dissolved by HF and the resultant amorphous a-BN film is used as a sample forming article 1 in ultrahigh pressure device and treated at 1500-1800 deg.C in 55-70Kb for 5-60min to provide the cubic BN polycrystal having <=0.1mum crystal size and 3.40-3.48g/cm<2> density. |
