Research On Property Of Metal Based Nano/Submicron Solid Self-lubricating Coating

In this paper, a series of experiments were carried out to test the bond strength, the microhardness, the friction coefficient and wear resistance of solid self-lubricant coatings which were prepared by YAG laser clad and HVOF spray craft. The influence of the existence of Nano/sub-micron sized lubricant phases on the property of solid self-lubricant coatings was researched during this test. A special apparatus was designed and manufactured to prepare the bond strength test samples in order to measure the bond strength of the HVOF sprayed coatings effectively as well as an effective method for evaluating the friction coefficient and wear resistance of solid self-lubricant coatings at both room temperature and high temperature was established. Factors which influence the friction and wear property of these coatings are researched.Microstructural analysis shows that a large amount of M7C3 exists in the coating. Lubricant phases distribute around M7C3 form a soft-hard alternate structure in YAG laser clad coatings. The microhardness of this kind of coating is HV800 or about, it is lower than the laser-clad coating prepared by pure Ni powder. The friction coefficient of YAG laser clad Ni60-BN and Ni60-WS2 coatings is about 0.37, it is about 30% lower than the friction coefficient of YAG laser-clad pure Ni60 coating (about 0.5~0.6). At room temperature, the wear resistance of YAG laser-clad Ni60-BN multiple-coating is five times or above better than YAG laser-clad pure Ni60 while the YAG laser-clad Ni60-WS2 multiple-coatings is ten times or above better than it. The wear resistance of YAG laser-clad Ni60-BN multiple-coating is four times or above better than YAG laser-clad pure Ni60 coating while the YAG laser-clad Ni60-WS2 multiple-coatings is three times or above better than it at 400℃.Nano solid self-lubricant coatings are prepared with HVOF spray craft, In this research the bond strength and the friction and wear property of these coatings is tested. Result shows that, the bond strength of HVOF sprayed coatings is about 20MPa, tension failure take place within the sprayed coating. This is partly caused by the poor consistency between backing and lubricant phases. The coating contain WS2 5% has the best frictional and wear property. Its friction coefficient decrease to about 0.35 while the friction coefficient between backing and GGr15 is about 0.5.