Glass-ceramic coatings for titanium-based metal surfaces
AssigneeCorning Incorporated
InventorsRonald L. Andrus, John F. MacDowell
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Abstract
An article of manufacture comprising protectively coated titanium, titanium alloy or titanium aluminide, and a method for making it, wherein the protective coating is an adherent crystalline alkaline earth silicate glass-ceramic coating having a composition consisting essentially, in weight percent on the oxide basis, of about 20-75% total of oxides selected in amounts not exceeding the indicated proportions from the group consisting of up to about 50% BaO, 55% SrO, and 35% CaO, 25-60% of SiO.sub.2 and, as optional constituents, 0-25% MnO, 0-20% MgO, and 0-30% total of other compatible bivalent and trivalent metal oxides. The coating is applied as a continuous glassy coating and is converted to a crystalline glass-ceramic coating by heat treatment.
Claims5
A method for protecting a substrate formed of a metal selected from the group consisting of titanium, titanium aluminides and titanium alloys from oxidation and chemical attack which comprises the steps of:
- applying to a surface of the substrate a continuous glassy coating of an alkaline earth silicate glass having a composition consisting essentially, in weight percent on the oxide basis, of about 20-75% total of oxides selected in amounts not exceeding the indicated proportions from the group consisting of up to about 50% BaO, 55% SrO, and 35% CaO, 25-60% of SiO.sub.2 and, as optional constituents, 0-25% MnO, 0-20% MgO, and 0-30% total of other compatible bivalent and trivalent metal oxides;
- and
- crystallizing the continuous glassy coating by heat treatment to provide an adherent, densely crystalline glass-ceramic coating on the substrate surface.
A coated article composed of a metal selected from the group consisting of titanium, titanium aluminides and titanium alloys wherein the metal is protected from oxidation by an adherent crystalline alkaline earth silicate glass-ceramic coating having a composition consisting essentially, in weight percent on the oxide basis, of about 20-75% total of oxides selected in amounts not exceeding the indicated proportions from the group consisting of up to about 50% BaO, 55% SrO, and 35% CaO, 25-60% of SiO.sub.2 and, as optional constituents, 0-25% MnO, 0-20% MgO, and 0-30% total of other compatible bivalent and trivalent metal oxides.
Dependencies are inferred from the claim text.