Papers by Author: Yong Kun Qin

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Authors: Yong Kang Zhang, Jian Liang Li, Dang Sheng Xiong, Yong Kun Qin
Abstract: The nickel-based boron nitride composite coatings were prepared by reversing pulse electro-deposition. The mechanical properties and friction behavior of the coatings at high temperature were tested by using Al2O3 ceramic ball at high temperature friction-testing machine. The results show that the surface micro-hardness of the coatings increases with the addition of BN powder. Meanwhile, the friction coefficient and wear rate of specimens decreases. Especially when the BN addition is 1.5g/L the composite coatings present a minimum of friction coefficient and wear rate. In optimum process parameters, the friction coefficient of the coatings is about 0.2 at room temperature and 0.4-0.5 at 600°C. In addition, the friction and wear properties were significantly improved by plating Ni transition layer plated between substrate and composite coating.
Authors: Jian Liang Li, Hang Li, Dang Sheng Xiong, Yu Juan Ji, Yong Kun Qin
Abstract: In this paper an adaptive Ni-Mo-Al-Ag-BN composite coating was deposited by plasmaspraying. Its tribological property from 20°C-600°C were evaluated by using high temperature tribometer. Scanning electron microscopy and Raman spectroscopy were used to characterize the coating and corresponding wear tracks to determine the lubrication mechanisms. The result shows that the friction coefficient of the Ni-Mo-Al–Ag-BN composite coating from 200°C to 400°C is about 0.4 and declines very slightly at 600°C . The wear rates of the coating is 2.0×10-4mm3/N*m at 600°C and the downward trend is obvious compared with 400°C. Silver provide lubrication below 400 °C. Ag2MoO4 were formed with the temperature raised, and acted as high-temperature lubricants above 400 °C. Ni-Mo-Al–Ag-BN composite coating established a new lubrication mechanism model at 600°C . It can be concluded that the plasma sprayed Ni-Mo-Al - Ag - BN composite coating can keep good tribological property at wide range of temperature.
Authors: Jian Liang Li, Juan Juan Chen, Dang Sheng Xiong, Yong Kang Zhang, Yong Kun Qin, Yong He
Abstract: The graphene containing Ni-based composite coatings with different graphene addition amounts were prepared on 45 steel surface by using dipulse composite electrodeposition technology. The tribological behavior of composite coating was tested by against GCr15 steel pin under the dry condition. The friction coefficient of composite coating is 20-30% lower than pure Cr coating, their wear rates are almost in the same magnitude. Compared with 45 steel, the friction coefficient of composite coating decreases and wear rate falls over 50%.
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