Coating system for providing environmental protection to a metal substrate, and related processes
OwnerWayne Charles Haszinventor
Life of this patent
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Abstract
A metal article which includes a protective coating system is described. The coating system includes a braze alloy layer and a plasma-sprayed bond coat. The bond coat may lie on top of the braze alloy layer, or the braze alloy layer may lie on top of the bond coat. In the case of a porous bond coat, partial or complete densification of the bond coat is sometimes carried out. Densification is achieved by heat treating the article, so that the braze alloy material migrates into the pores of the bond coat to a selected thickness. Related processes are also described.
Claims49
An article, comprising a metal-based substrate, and at least two layers overlying the substrate, wherein one of the layers is a coating which comprises a braze alloy, and another layer is a plasma-sprayed bond coat.
An article, comprising:
- (i) a nickel-base superalloy substrate;
- (ii) a braze alloy layer lying directly over the substrate, and comprising a nickel-base or cobalt-base material;
- (iii) a plasma-sprayed bond coat lying directly over the braze alloy layer, and comprising an alloy of the formula MCrAlY, where M is selected from the group consisting of Fe, Ni, Co, and mixtures of any of the foregoing;
- and
- (iv) a zirconia-based thermal barrier coating, applied directly over the bond coat.
An article, comprising:
- (i) a nickel-base superalloy substrate;
- (ii) a plasma-sprayed bond coat lying directly over the substrate, and comprising an alloy of the formula MCrAlY, where M is selected from the group consisting of Fe, Ni, Co, and mixtures of any of the foregoing;
- (iii) a braze alloy layer lying directly over the plasma-sprayed bond coat;
- and
- (iv) a zirconia-based thermal barrier coating, applied directly over the braze alloy layer.
An article, comprising:
- (i) a metal-based substrate;
- (ii) a dense bond layer over the substrate;
- (iii) a substantially porous bond layer over the dense bond layer, having a microstructure which comprises an open network of interconnected pores;
- and
- (iv) a thermal barrier coating over the substantially porous bond layer;
- wherein the dense bond layer has been formed by a heat-induced infiltration of a braze material into a porous bond region immediately below layer (iii).
A method for providing environmental protection to a metal-based substrate, comprising the steps of applying a coating which comprises a braze alloy over the substrate, and plasma-spraying a bond coat over the substrate.
A method for providing environmental protection to a nickel-base superalloy substrate, comprising the following steps:
- (i) applying a braze alloy coating on the substrate, said coating comprising silicon, chromium, and nickel;
- (ii) plasma-spraying a bond coat over the braze alloy coating, said bond coat comprising an alloy of the formula MCrAlY, where M is selected from the group consisting of Fe, Ni, Co, and mixtures of any of the foregoing;
- (iii) applying a zirconia-yttria thermal barrier coating over the bond coat;
- and
- (iv) heat treating the braze alloy coating, to at least partially densify the bond coat.
Dependencies are inferred from the claim text.