Abstract:In order to improve the corrosion resistance of magnesium alloy, this study used cold spraying process to prepare aluminium coating on ZM6 magnesium alloy substrate, investigated the effect of cold spraying process parameters (gas temperature, pressure, spraying distance and pressure) on the quality of aluminium coatings, and came up with the optimum process parameters and prepared aluminium coatings using the optimum process parameters for salt spray test. The test results show that: the optimum process parameters for cold spraying aluminium coating are temperature 310 ℃; gas pressure 2.0 MPa; optimum distance of spraying 20 mm; and relative movement speed of the substrate 30-50 mm.s-1. The corrosion products of salt spray corrosion of cold sprayed aluminium thin coatings are Al2O3, Al(OH)3, Mg(OH)2, and MgCl2. With the growth of time, the thin aluminium coatings are punctured and galvanic coupling corrosion with magnesium alloy occurred, accelerating the corrosion of the substrate. The thick coating of cold sprayed aluminium produced a better protective effect on the magnesium alloy substrate due to the formation of a dense and continuous oxide film on the surface, which hindered the intrusion of corrosive media.The salt spray resistance time of the thick coating of cold sprayed aluminum prepared using the optimal process parameters exceeds 1200 hours.