In the "Micro Cooling Fan" designs, often using surface treatment methods, such as flanges, zinc, chrome, chemical plating and other methods, these methods are effective in many environments, but for rotating parts, must pay attention to an important Phenomenon: the base material and the coating material are two, "Micro Cooling Fan" coefficient of linear expansion is different, will produce the same amount of deformation during the rotation of the elastic deformation, resulting in the generation of a large number of microcracks; if the foregoing phenomenon exist, it will accelerate the formation of corrosion. Thus, for Surface Protection "Micro Cooling Fan" rotating parts should be used with caution. At the time of purchase, to use appropriate materials and processes based on our environment.