Cast product having aluminum-based film and process for producing the same
AssigneeKeihin Corporation
InventorsBotaro Watanabe, Takeshi Hirama
Life of this patent
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Abstract
In a throttle body, a passive film and a corrosion-resistant film are stacked in that order on a substrate of aluminum. The passive film has a concave part on its corrosion-resistant film side. A metal layer is provided in the concave part. In shot blasting, upon collision of a blasting material against the corrosion-resistant film, a part of the blasting material is separated and adhered onto the resultant concaves to form the metal layer. For example, aluminum having a purity of not less than 98% is selected as the blasting material.
Claims9
A cast product having an aluminum-based film comprising a base material which has a passivation film formed on a surface of an underlying material composed of aluminum or aluminum alloy, and a corrosion-resistant coating film with which said passivation film is coated and which has corrosion resistance higher than that of said underlying material, wherein:
- recesses are formed on a side of said corrosion-resistant coating film on said passivation film;
- and
- a metal layer, which is composed of aluminum having a purity of not less than 98%, zinc having a purity of not less than 98%, or aluminum-zinc alloy having a purity of not less than 98%, exists in each of said recesses.
A method of producing a cast product having an aluminum-based film, comprising the steps of:
- obtaining a cast product by performing a casting process using a molten metal of aluminum or aluminum alloy;
- blasting said cast product having a passivation film with a blasting material composed of aluminum having a purity of not less than 98%, zinc having a purity of not less than 98%, or aluminum-zinc alloy having a purity of not less than 98%, to provide recesses on said passivation film and to form a metal layer originating from said blasting material in each of said recesses;
- and
- providing, on said passivation film, a corrosion-resistant coating film having corrosion resistance higher than that of aluminum or aluminum alloy.
Dependencies are inferred from the claim text.