由于较高的综合力学性能，氮化硅陶瓷球得到广泛的工程应用，但是极端工况下依然存在明显失效开裂现象。在一般氧化物烧结助剂的基础上添加少量过渡金属化合物能起到优化材料设计和进一步提高性能的作用，但是相关作用机理还未有明确探知。在添加Al2O3和Y2O3烧结助剂基础上，分别添加TiN、Fe3Si和WC等过渡金属化合物，并采用热等静压烧结方法制备了氮化硅陶瓷轴承球。采用X射线衍射检测其物相组成，采用扫描电子显微镜和透射电子显微镜研究其组织结构特点，并使用纳米压痕法对其力学性能进行了研究。结果表明，添加TiN可有效抑制烧结过程中有害物相Si2N2O的生成；添加TiN和WC有利于烧结过程Al和O向氮化硅基体中扩散，形成了Sialon相；添加Fe3Si则不具有上述作用；添加TiN可获得晶粒尺寸细小均匀的β-Si3N4组织；添加Fe3Si会生成粗大β-Si3N4晶粒相互穿插桥接且其空隙填充细小β-Si3N4晶粒的烧结组织；添加WC则生成粗细晶共存的非均匀组织。与添加Fe3Si和WC相比，添加TiN的氮化硅陶瓷球具有更高的硬度和更大的弹性模量等更好的力学性能。

Three silicon nitride ceramic balls were prepared via hot static pressing (HIP). In addition to some conventional sintering aids like Al2O3 and Y2O3, TiN, Fe3Si and WC transition metal compounds were incorporated into the powder mixtures before ball-milling and HIP, respectively. The microstructures and mechanical properties of the silicon nitride ceramic balls prepared were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nano indentation (NI) analysis. The results indicate that TiN additive has an effect of suppressing the formation of Si2N2O during sintering. TiN and WC additives can promote the diffusion of Al and O into silicon nitride matrix during sintering, resulting in the formation of some sialon phase. However, Fe3Si additive has little effect as mentioned above. TiN additive has an effect of refining the microstructure, thus obtaining a refined grain structure with an even size distribution. Fe3Si additive tends to produce a microstructure of long-coarse-grain intersected and bridged frame filled by grains. WC additive leads to the development of an uneven microstructure containing the coarser and finer grains. Compared to the balls containing Fe3Si or WC additives, the ball containing TiN additive has better mechanical properties, i.e., higher hardness and greater modulus of elasticity.