TiB_2/WC/h-BN自润滑陶瓷材料的制备及力学性能

Preparation and Mechanical Properties of TiB_2/WC/h-BN Self-lubricating Ceramic Material

通过添加固体润滑剂h-BN,采用真空热压烧结工艺制备TiB2/WC/h-BN自润滑陶瓷材料,对其密度和力学性能进行测试,并采用XRD和SEM对材料的物相和显微结构进行分析。结果表明:TiB2/WC/h-BN自润滑陶瓷材料的相对密度为97.5%,抗弯强度、断裂韧性和维氏硬度分别为652MPa、4.5MPa·m1/2和14.8GPa。片状结构的固体润滑剂hBN颗粒保存完整,分布均匀,而且可有效抑制基体TiB2晶粒的长大。材料的断裂模式是穿晶/沿晶断裂的混合型,以穿晶断裂为主。材料的增韧机理以裂纹偏转和裂纹桥联为主。TiB2/WC/h-BN自润滑陶瓷材料的摩擦因数低于0.3,与其他添加h-BN的自润滑陶瓷材料相比,具有良好的力学性能和摩擦性能。

TiB2/WC/h-BN self-lubricating ceramic material with the addition of solid lubricant h-BN was prepared with vacuum hot-pressing sintering technique.Mechanical properties and density were tested.The phase and microstructure of the material were analyzed by X-ray diffraction and SEM.The results show that the relative density of TiB2/WC/h-BN self-lubricating ceramic material is 97.5％,and its flexural strength,fracture toughness and Vickers hardness are 652MPa,4.5MPa · m1/2 and 14.8GPa,respectively.Solid lubricant h-BN particles with flake structure are intact and uniformly distribute.It can effectively inhibit the growth of TiB2 matrix grains.The fracture of the material belongs to the mixture of transgranular/intragranular mode but mainly transgranular fracture.The toughening mechanisms are mainly crack bridging and crack deflection.The friction coefficient of TiB2/WC/h-BN self-lubricating ceramic material is lower than 0.3.Compared with the other self-lubricating ceramic materials added h-BN,TiB2/WC/h-BN self-lubricating ceramic material has better mechanical properties and friction behavior.