Engine part
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorNaohisa Takahashi
Life of this patent
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Abstract
An engine part has a construction which prevents the surface discoloration/deterioration associated with a high-temperature exhaust gas, irrespective of the type of Cr used in the formation of a chromium plating layer (hexavalent chromium or trivalent chromium). The engine part includes a metal substrate, a chromium plating layer covering at least a region of a surface of the metal substrate, the region being heated to a temperature of about 350° C. or more, and an intermediate plating layer provided between the metal substrate and the chromium plating layer. The chromium plating layer has a thickness of about 0.2 μm or more in the region.
Claims30
An engine part comprising:
- a metal substrate;
- a chromium plating layer covering at least a region of a surface of the metal substrate, the region being heated to a temperature of about 350° C. or more;
- and
- an intermediate plating layer provided between the metal substrate and the chromium plating layer;
- wherein
- the chromium plating layer has a thickness in a range from about 0.2 μm to about 0.9 μm in the region;
- the chromium plating layer includes decorative chromium plating;
- and
- the intermediate plating player includes at least one of C and S.
An engine part comprising:
- a metal substrate;
- a chromium plating layer covering at least a portion of a surface of the metal substrate;
- and
- an intermediate plating layer provided between the metal substrate and the chromium plating layer;
- wherein
- a type of Cr composing the chromium plating layer substantially has an amorphous structure, and an Fe content in the chromium plating layer is about 2 mass % or less;
- the chromium plating layer covers a region of the surface of the metal substrate, the region being heated to a temperature of about 350° C. or more, and the chromium plating layer has a thickness in a range from about 0.2 μm to about 0.6 μm in the region:
- the chromium plating layer includes decorative chromium plating;
- and
- the intermediate plating layer includes at least one of C and S.
An exhaust pipe comprising:
- a metal tube having a bent portion;
- a decorative chromium plating layer arranged so as to cover at least an outer convex surface being defined by a portion of the bent portion, the decorative chromium plating layer having a thickness in a range from about 0.2 μm to about 0.5 μm;
- and
- an intermediate plating layer provided between the bent portion and the decorative chromium plating layer;
- wherein
- the intermediate plating layer includes at least one of C and S.
Dependencies are inferred from the claim text.