THERMAL BARRIER COATING SYSTEMS AND PROCESSES THEREFOR

摘要

Coating systems and processes by which the coating systems can be deposited to be resistant to contaminants, and particularly resistant to infiltration and damage caused by CMAS. The coating systems include inner and outer ceramic layers. The inner ceramic layer consists essentially of zirconia stabilized by about 6 to about 9 weight percent yttria and optionally contains greater than 0.5 to 10 weight percent hafnium oxide. The outer ceramic layer overlies and contacts the inner ceramic layer to define the outermost surface of the coating system. The outer ceramic layer consists essentially of zirconia stabilized by about 25 to about 75 weight percent yttria, has a thickness that is less than the thickness of the inner ceramic layer and further contains greater than 0.5 to 10 weight percent hafnium oxide and optionally 1 to 10 weight percent tantalum oxide. The outer ceramic layer has a porosity level that is lower than that of the inner ceramic layer.

主权项

1. A coating system on a surface region of a component, the coating system comprising:
a bond coat; and inner and outer ceramic layers on the bond coat, the inner ceramic layer overlying the bond coat, the inner ceramic layer consisting essentially of zirconia stabilized by about 6 to about 9 weight percent yttria, the inner ceramic layer having a thickness and a porosity level, the outer ceramic layer overlying and contacting the inner ceramic layer and defining an outermost surface of the coating system, the outer ceramic layer consisting essentially of zirconia stabilized by about 25 to about 75 weight percent yttria and further containing greater than 0.5 to 10 weight percent hafnium oxide and optionally 1 to 10 weight percent tantalum oxide, the outer ceramic layer having a thickness that is less than the thickness of the inner ceramic layer and having a porosity level that is lower than the porosity level of the inner ceramic layer.