| Summary: | 碩士 === 國防大學理工學院 === 車輛及運輸工程碩士班 === 98 === This research purpose was to evaluate the tribological properties of brush plating nickel alloy coatings and nickel based composite coatings by tribological tests and measurements. In this study, four different types of coatings such as Ni alloy coatings, Ni-SiC, Ni-WC, and Ni-Al2O3 composite coatings were prepared by brush plating techniques. Variable factors of the plating process include electrical voltage, the quantity of current time and nano ceramic particles. For this work, a reciprocating wear test machine was used to carry out these tribological experiments under dry lubrication and normal environment. The tribological mechanisms of Ni base alloy nano composite coatings can be clearly examined by the measurements including coefficient of friction (COF), wear resistance, and the view of wear morphology combined the elements which detected on the worn surfaces.
Experimental results were shown the following evidences : The Ni-SiC coatings have the highest hardness valve up to 705 HV and the corresponding COF is lower about 12% than that of Ni coating. The Ni-WC coatings have the hardness value up to 558 HV and the corresponding COF is lower 21% than that of Ni coating. The Ni- Al2O3 coatings have the hardness value up to 568 HV and the corresponding COF is lower 15% than that of Ni coating. The Ni-Al2O3 composite coatings with excellent wear resistance that may be caused by well dispersed of alumina particle in the coating layer, and leading to enhance the resisting of abrasive from the count ball body. It is also shown from the observation of the wear morphology that the departed nano alumina particles would be formed a part of rolling friction mechanism in the interface of sliding contact surfaces, and leading to decrease the COF and enhance the wear resistance.
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