Thermal barrier coating protected by alumina and method for preparing same

摘要

A thermal barrier coating (22) for an underlying metal substrate (14) of articles (10) that operate at, or are exposed, to high temperatures, as well as being exposed to environmental contaminant compositions. This coating (22) comprises an optional inner layer (26) nearest to the underlying metal substrate (14) comprising a non-alumina ceramic thermal barrier coating material in an amount up to 100%, and an outer layer (30) having an exposed surface (34) and comprising at least 50% of a non-alumina ceramic thermal barrier coating material and alumina in an amount up to 50% and sufficient to protect the thermal barrier coating (22) at least partially against environmental contaminants that become deposited on the exposed surface (34). This coating (22) can be used to provide a thermally protected article (10) having a metal substrate (14) and optionally a bond coat layer (18) adjacent to and overlaying the metal substrate (14). The thermal barrier coating (22) can be prepared by optionally forming the inner layer (26) of the non-alumina ceramic thermal barrier coating material, and then codepositing the alumina and non-alumina ceramic thermal barrier coating material to form the outer layer (30).