Process for preparing aluminum-silicon seal coating

The invention relates to a process for preparing an aluminum-silicon seal coating, which comprises the steps of: washing a base body surface, protecting non-coated surfaces, sandblasting till no bright spot exists on the surface, protecting the non-coated surfaces of components, coating the nickel-aluminum bottom layer and surface layer, clearing remainders on surfaces of clamps and the components, processing mold surfaces by a numerical control lathe, inspecting and putting in a storage. Compared with a nickel-graphite coating, the aluminum-silicon coating has the advantages of simple process, low cost, wear resistance, easy processing on coating surface, high surface finishment, no chipping, reliable binding with the base body and no wearing on rotor vanes. Experiments show that the usage temperature of the aluminum-silicon coating reaches 450 DEG C. A combined gas compressor adopting the aluminum-silicon coating has higher pressure ratio than the gas compressor adopting the nickel-graphite coating and the