Si3N4-hBN陶瓷复合材料与Fe-B合金配副的摩擦学特性研究

摘要

The tribological behaviors of Si3N4-hBN composites sliding on Fe-B alloy without lubrication and with water lubrication were studied on a MMU-5G type pin-on-disc wear tester. The results show that the addition of hBN to Si3N4 can not effectively improve the tribological characteristics of Si3N4-hBN/Fe-B alloy sliding pairs. The materials and worn surfaces as well as wear debris were characterized by means of scanning electron microscopy ( SEM ) and X-ray diffraction ( XRD) , and the worn surfaces were analyzed by using X-ray diffraction spectroscopy ( EDS) , laser scanning microscopy ( LSM) and X-ray photoelectron spectroscopy ( XPS). The analysis indicates that, without lubrication, the wear of Si3N4-hBN composites is resulted from cracking and fracture,while the hard phase Fe2B in Fe-B alloy spall off during the wear test. This results in the abrasive wear,high friction coefficients( >0. 9)and high wear coefficients( >1 ×10-5 mm3/(N ? M)). With water lubrication, the wear debris is carried away from wear surfaces by water stream, and the abrasive wear is avoided. The wear surfaces become smooth due to the chemical removal of micro-asperities on Si3N4-hBN surface caused by successive oxidation and hydrolysis of Si3N4 and hBN. As a result, excellent tribological characteristics of Si3N4-hBN/Fe-B alloy pairs are obtained.%利用MMU-5G销-盘式端面磨损试验机考察Si3N4-hBN陶瓷复合材料与Fe-B合金配副分别在干摩擦和水润滑条件下的摩擦磨损性能,分别采用扫描电子显微镜( SEM)、激光扫描显微镜(LSM)、X光电子能谱(XPS)、X射线能谱(EDS)和X射线衍射(XRD)分析摩擦面及磨屑的形貌与物质组成.结果表明,hBN的加入未能有效地改善Si3N4-hBN/Fe-B合金摩擦副的摩擦学性能,干摩擦条件下,Si3N4-hBN摩擦表面微凸体与Fe-B合金中的硬质相Fe2B发生碰撞而导致脆性断裂和剥落,发生磨粒磨损,摩擦因数均高于0.9,磨损率均高于10-5 mm3/ (N·m)数量级；水润滑条件下,由于水流带走了磨屑,避免磨粒磨损的发生,为Si3N4-hBN摩擦表面发生化学抛光提供条件,化学抛光使销、盘试样的摩擦表面变得光滑,从而获得较为优异的摩擦学性能.