以Y₂O₃为烧结助剂,采用放电等离子烧结技术制备了以MoSi₂为第二相的α-Sialon陶瓷,研究了MoSi₂添加量(0~10%,质量分数)对陶瓷微观结构和性能的影响。结果表明:添加MoSi₂后,陶瓷中α-Sialon晶粒从等轴状变为长棒状,且随着MoSi₂添加量的增多,长棒状α-Sialon晶粒显著增多,长径比增大,当MoSi₂质量分数为10%时,晶粒尺寸呈现显著的双峰分布;当MoSi₂质量分数从0增加到10%时,陶瓷的相对密度由99.0%增加到99.7%,硬度由21.12 GPa降低到20.44 GPa,断裂韧度由4.80 MPa·m^1/2增加到6.13 MPa·m^1/2;在干切削镍基高温合金时,添加质量分数10% MoSi₂的陶瓷刀具在达到磨损标准时的切削长度是未添加MoSi₂陶瓷刀具的1.5倍,可见该刀具切削性能优异,其主要磨损形式为后刀面磨损和沟槽磨损,主要磨损机理为黏着磨损和磨粒磨损。

Using Y₂O₃ as sintering aid, α-Sialon ceramics with MoSi₂ as a second phase were prepared by spark plasma sintering. The effect of the MoSi₂ adding amount (0-10wt%) on the microstructure and properties of the ceramics was studied. The results show that after adding MoSi₂, the α-Sialon grains in the ceramics changed from equiaxed to long rod-like. With increasing MoSi₂ adding amount, the long rod-like α-Sialon grains increased significantly, and the aspect ratio increased; when the addition of MoSi₂ was 10wt%, the grain size exhibited a significant bimodal distribution. When the addition of MoSi₂ increased from 0 to 10wt%, the relative density of the ceramics increased from 99.0% to 99.7%, the hardness decreased from 21.12 GPa to 20.44 GPa, and the fracture toughness increased from 4.80 MPa·m^1/2 to 6.13 MPa·m^1/2. In dry cutting of nickel-based superalloy, the cutting length of the ceramic tool with 10wt% MoSi₂ was 1.5 times that of the ceramic tool without MoSi₂ when it reached the wear standard, indicating the tool had excellent cutting performance; the main wear forms of the tool were flank wear and groove wear, and the main wear mechanisms were adhesive wear and abrasive wear.