Study on corrosion resistance of aluminium coating deposited on magnesium-zinc-yttrium-calcium alloy by cold sprayStudie über die Korrosionsbeständigkeit von durch Kaltgasspritzen aufgebrachten Aluminiumbeschichtungen auf Magnesium-Zink-Yttrium-Calcium-Legierungen

Pure aluminium coatings were prepared on magnesium-zinc-yttrium-calcium alloy substrate via cold spraying technology with different scanning speeds and working gas temperature. The correlation between the corrosion resistance of the coatings and the different spraying process was studied. While the working gas temperature is 600 degrees C and the scanning speed is 1 mm/s, aluminium coating has less porosity and the coating was well combined with the substrate. Higher temperature of working gas increases the plastic deformation of particles, which lead to a dense aluminium coating. The relationship of corrosion resistance on working gas temperature and scanning speed of aluminium coatings has also been investigated by immersion corrosion test and electrochemical impedance spectroscopic techniques. The results show that the cold sprayed aluminium coatings revealed a lower porosity and higher corrosion resistance with the decreasing scanning speed and the increasing temperature of working gas. The porosity and corrosion current densities were 0.938 vol.% and 2.427 & sdot; 10-6 A/cm2. The experimental results show that the aluminium coating prepared by cold spraying has a good protective effect on magnesium alloy. Aluminium coating on magnesium alloy substrate was prepared with aluminium particles of poor sphericity by a self-designed cold spray equipment. The cold sprayed aluminium coatings revealed a low porosity and good corrosion protection at the scanning speed of 1 mm/s and the working gas temperature of 600 degrees C.image