一种自润滑陶瓷摩擦磨损性能的研究

采用热压成型工艺制备了Al2O3/TiC/CaF2自润滑陶瓷材料,测试了其机械性能,并在MRH-3型摩擦磨损试验机上研究了其在室温下的摩擦磨损性能,利用扫描电子显微镜观察分析了磨损表面形貌,进而研究了其摩擦磨损机理.结果表明:当CaF2含量为10%时,Al2O3/TiC/CaF2材料具有较好的力学性能;Al2O3/TiC/CaF2材料的摩擦系数随CaF2含量、载荷和速度的增加而降低;Al2O3/TiC/CaF2材料在高速摩擦条件下能够在磨损表面形成一层固体润滑膜,正是由于这层膜的存在使得其在高速、高载荷下具有较低的摩擦系数,而低速下其磨损机理主要是磨粒磨损,很难形成较完整的润滑膜,由于机械应力和热应力的共同作用,自润滑膜在反复摩擦下产生裂纹,从而导致其破坏.

Friction and Wear Behavior of Self-lubricating Ceramic Composite

Al_2O_3/TiC self-lubricating ceramic material with addition of CaF_2 was produced by hot pressing.Friction and wear behaviors of the self-lubricating material were investigated on an MRH-3 ring-on-block friction and wear tester under dry friction,and worn surface morphologies were observed on a scanning electron microscope.It was found that the composite with 10% CaF_2 content showed higher bend strength,fracture toughness,and hardness compared with that of the composites with 5% and 15% CaF_2 content owing itsporosity absent and finer microstructure.Friction coefficient is reduced with increasing of CaF_2 content,speed and load individually.A lubricating layer was generated on the worn surfaces under high speed and load,which accounted for the friction-reducing and antiwearability of the self-lubricating material at high speed and load.While at low speed,abrasive wear is the main wear mode and the lubricating layer is difficultly generated.But solid lubricant existing between friction surfaces can still contribute to reducing the friction coefficient.Cracks were found on the surface of the self-lubricating film under repeated frictional condition because of mechanical stress and thermal stress.