Methods for making environmental barrier coatings and ceramic components having CMAS mitigation capability

摘要

Methods of making components having calcium magnesium aluminosilicate (CMAS) mitigation capability include providing a component, applying an environmental barrier coating to the component, where the environmental barrier coating includes a CMAS mitigation composition selected from the group consisting of zinc aluminate spinel, alkaline earth zirconates, alkaline earth hafnates, rare earth gallates, beryl, and combinations thereof.

主权项

1. A method of making a component having calcium magnesium aluminosilicate (CMAS) mitigation capability, the method comprising:
providing a component comprising a ceramic matrix composite or a monolithic ceramic; applying an environmental barrier coating to the component, the environmental barrier coating comprising: a bond coat layer comprising silicon overlying the component; an optional silica layer overlying the bond coat layer; at least one transition layer overlying the bond coat layer or the optional silica layer comprising a composition selected from the group consisting of mullite, barium strontium aluminosilicate (BSAS), rare earth disilicates, and combinations thereof; an optional outer layer comprising an outer layer material selected from the group consisting of BSAS, rare earth monosilicates, rare earth disilicates, and combinations thereof; and a separate CMAS mitigation layer overlying the at least one transition layer or the optional outer layer, wherein the separate CMAS mitigation layer consists of Lna4Ga2O9 and optionally one or more compositions selected from the group consisting of zinc aluminum spinel, alkaline earth zirconates, alkaline earth hafnates, rare earth aluminates, rare earth gallates, beryl, and combinations thereof, wherein the separate CMAS mitigation layer contains Lna4Ga2O9 in an amount sufficient to prevent degradation of the environmental barrier coating due to reaction with CMAS.