| 摘要 |
PURPOSE:To obtain silicon nitride powder whose particles each has a crystalline inner part and a surface covered with an amorphous layer having a specific composition, and which gives highly strong and highly reliable sintered compacts, by subjecting a surface treatment to silicon nitride powder. CONSTITUTION:Commercial silicon nitride powder is subjected to various surface treatments such as a thermal surface oxidation reaction in the atmosphere, a thermal surface modification in the atmosphere of a gas mixture comprising O2, N2, H2, steam, etc., and a surface oxidation or nitridation by plasma, etc. Thus, silicon nitride powder whose particles each has a crystalline inner part and a surface covered with an amorphous layer consisting mainly of Si, N, O and H and having a thickness of >=10nm. The surface of the powder preferably has an oxygen/nitrogen atomic number (O/N) ratio of >=2 and further preferably gives an aqueous solution exhibits a pH of 8-13, when immersed in neutral water or hot water. The employment of the produced silicon nitride powder enables to obtain compacts having homogeneously powder-filled structures, respectively. |
