Papers by Author: Wen Ping Liang

Abstract: New waterborne Al-Zn-Si-RE coatings with improved corrosion resistance were introduced in this study. The corrosion resistance of Al-Zn-Si-RE coatings was evaluated by electrochemical measurements and salt spray test. Evolution of microstructure and phase composition at different exposure time in salt spray test was investigated by scanning electron microscopy and X-ray diffraction technique. The results indicate that Al-Zn-Si-RE coatings provide effective sacrificial protection to the steel substrate but exhibit lower corrosion rate and higher corrosion resistance compared to zinc aluminum coatings. The dense continuous corrosion layer formed on Al-Zn-Si-RE coating acts as a barrier layer, limiting the transport of aggressive species towards the coating-substrate interface and the corrosion rate of the coating; Zinc aluminum hydroxy carbonates are the dominant components in the corrosion layer of Al-Zn-Si-RE coatings.

Abstract: In order to improve the wear resistance of Ti2AlNb orthorhombic alloy, the carburized coating has been successfully prepared on Ti₂AlNb alloy by double glow plasma technology. The microstructure, chemical composition and phase structure o f the carburized coating were analyzed by means of SEM, EDS and XRD. The Micro hardness of the alloy layer was measured, and the bond strength of carburized coating with substrate was also evaluated by scratch test. The tribological behaviors of layer were investigated by friction-wear test. The results show that a carburized layer is formed which is about 40μm and the content of C gradient decrease after double glow plasma carburizing, the Micro hardness of the layer is 1051 HV0.1 and the bond of the coating is 62N, the tribological behavior of layer is much better than matrix.

Abstract: This paper was directed at improving the wear resistance of titanium alloy Ti6Al4V by double-glow plasma surface alloying (DPSA) technology. A molybdenized layer was successfully formed on Ti6Al4V by the DPSA treatments. The microstructure, composition distribution, phase structure and hardness were analyzed by SEM/EDS, XRD and vickers micro-hardness tester. The molybdenized layer was composed of Mo-deposited layer and Mo-diffusing layer. The average surface micro-hardness of the surface modified layer was 1170.8 HV_0.1, which was much higher than that of the Ti6Al4V substrate. Tribological characterization was carried out by the ball-on-disc tribometer at room temperature and 500°C. The molybdenized layer significantly reduced the wear rate of the Ti6Al4V alloy, which is only about 6.6% and 4.9% of those of the untreated specimens at room temperature and 500°C, respectively. Due to the good self-lubricating effect of Mo elements at high temperature conditions, the friction coefficient and wear rate of the molybdenized layer were both reduced at 500°C, compared to at room temperature.