Preparation of Electrodeposited Mo-Ni Coating in Weak Acid Solution

Abstract

Mo-Ni coatings were prepared on Ni alloy by electrodeposition method. The effects of sodium fluoride mass concentration, sodium chloride mass concentration, sodium molybdate mass concentration and pH value on deposition rate of Mo-Ni coating were researched, respectively. The morphology of Mo-Ni coatings were characterized with scanning electron microcopy (SEM). When sodium fluoride mass concentration is 12 g/L, deposition rate of Mo-Ni coating is as high as 0.3781 mg/cm2·min. When sodium chloride mass concentration is 22.3 g/L, deposition rate of Mo-Ni coating is as high as 0.2108 mg/cm2·min. When sodium chloride mass concentration, sodium molybdate mass concentration and pH value are 22.3 g/ L, 12 g/L and pH 5 respectively, deposition rate of Mo-Ni coating is as high as 0.2123 mg/cm2·min. There are many cracks and pits on the surface Mo-Ni coating deposited in the bath without adding NaCl or NaF, and coating surface is very uneven. The surface Mo-Ni coating deposited in the bath adding NaCl is smooth, and the grains of Mo-Ni coating is small. The surface Mo-Ni coating deposited in the bath adding NaF is smooth, and there are many nodules on the surface Mo-Ni coating.