| 摘要 |
PURPOSE:To obtain the title sintered form of high density and high mechanical strength with reduced variation in characteristics, by granulation of a mixture comprising Si3N4 powder, a sintering aid and a binder so as to result in a specific granular size, followed by forming and calcination. CONSTITUTION:Firstly, 100pts.wt. of Si3N4 powder 0.3-1.5wt.% in carbon content and >=90% in alpha-conversion rate is incorporated with 0.3-30pts.wt. of a sintering aid comprising 0.1-10pts.wt. of yttria, 0.1-10pts.wt. of alumina and 0.1-10pts.wt. of AlN followed by wet mixing grinding so that the resultant particle size distribution is such as D10=0.5-0.6mum, D50=1.5-2.0mum and D90=3.5-5.0mum. Thence, this mixed powder is spiked with a binder (e.g., PVA) followed by granulation so as to be 100-150mum in mean size and <=250mum in maximum size. The resulting granulated powder is then formed into a form >=30mm in thickness, which is then calcined at 1,700-1,850 deg.C. |
