The rapid solidified Al-12Si-3Fe-3Mn-2Ni alloy powders have been sprayed on the surface of magnesium alloy with cold spray technology.The diffusion law of Mg and Al element between coating and substrate alloy has been studied by different heat temperate and preserve time.The result shows that a diffusion layer can be formed between coating and substrate alloy.The thickness and homogeneous of diffusion layer have some relationship with heat treatment temperature and holding time.The diffusion capacity of Mg element diffused into coating from substrate alloy is more than that of Al element diffused into substrate alloy from coating.When heat treatment temperature and holding time go some level

the thickness of diffusion layer will not change.Therefore

diffusion heat treatment technology for cold spray coating has a suitable scope of technology parameter.