Dense protective coatings, methods for their preparation and coated articles

摘要

A method for depositing a protective coating on a complex shaped substrate includes the steps of: (1) dipping a complex shaped substrate into a slurry to form a base coat thereon, the slurry comprising an aqueous solution, at least one refractory metal oxide, and at least one transient fluid additive present in an amount of about 0.1 percent to 10 percent by weight of the slurry; (2) curing the dipped substrate; (3) dipping the substrate into a precursor solution to form a top barrier coat thereon; and (4) heat treating the dipped, cured substrate to form a protective coating.

主权项

1. A method for depositing a protective coating on a complex shaped substrate, comprising the steps of:
(1) forming a base coat on a complex shaped substrate comprising a gas turbine engine component by dipping said complex shaped substrate into a slurry consisting of an aqueous solution, at least one refractory metal addition of at least 25 mol. % of a first refractory metal oxide selected from the group consisting of hafnium oxide and monoclinic hafnium oxide and up to about 25 mol. % of at least one second refractory metal oxide, a dispersing agent in an amount no more than 50 percent weight of the slurry, and at least one transient fluid additive being a source of silica or titania, said transient fluid additive being present in an amount of about 0.1 percent to 10 percent by weight of said slurry and being used to promote grain growth and eliminate the formation of pores between grains; (2) curing said dipped substrate, wherein curing comprises heating said substrate to a temperature of between about 1250° C. to 1450° C. for about 30 minutes to 500 minutes; (3) dipping said substrate into a precursor solution to form a top barrier coat thereon; and (4) heat treating said dipped, cured substrate to form a protective coating.