| 摘要 |
PURPOSE:To improve thermal conductivity by controlling Al and oxygen amount contained as impurities to specific value or below and enhancing the density to a specific value or above. CONSTITUTION:The objective Si3N4 sintered compact consists of silicon nitride, having <=3.5wt.% Al and <=3.5wt.% oxygen contained as impurities, >=3.15g/cm<2> density thereof and >=40W/m thermal conductivity thereof. The sintered compact has high thermal conductivity and simultaneously has light-transmitting property which did not exist in a conventional Si3N4 sintered compact. It is required to severely control particle diameter or purity of raw material Si3N4 powder in order to produce the objective sintered compact and the particle diameter is controlled to <=2mum and oxygen content is controlled to <=1.5wt.% and total amount of anionic and cationic impurities such as Al, O, C, etc., subjected to solid-solution is controlled to <=1.0wt.%. Such the powder can be synthesized by a reducing nitriding method of SiO2 powder or nitriding method of metal Si and organosilicon compound, especially preferably nitriding method of Si imide compound or alkyl compound. |
