| Summary: | 碩士 === 清雲科技大學 === 機械工程系所 === 97 === This study used electroplating process to prepare Ni/nano-TiO2 composite coating on 7075-T6 aluminum alloy surface after various anodizing treatments (anodizing potentials: -0.75V、-1V、-1.25V、-1.5V; anodizing time:1800s) to obtain a medium layer, then performing the electroplating in 30 min by adding 1 g/L and 10 g/L TiO2 (15nm) to nickel plating solution. The surface morphology, element composition and surface hardness of the coatings were analyzed by using SEM, EDS and Vicker’s hardness tester. The corrosion and wear-corrosion resistance of electroplating Ni/nano-TiO2 composite coating in 3.5% NaCl solution was evaluated, also discussing with the related micro-structural analysis results.
Experimental results indicated that electroplating Ni/nano-TiO2 composite coating has high hardness, good corrosion resistance, particularly owing to the anodizing treatment of aluminum alloy. The anodizing treatment of 7075-T6 aluminum alloy substrate efficiently improved the adhesion, surface morphology and hardness of the electroplated Ni/nano-TiO2 composite coating. The optimal anodizing condition was at anodizing potential of -1V, time of 1800s. The incorporation of TiO2 at high concentration of 10 g/L significantly increased the corrosion and wear-corrosion resistance of Ni/nano-TiO2 composite coating in 3.5 wt.% NaCl solution.
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