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, each having a microstructure characterized by splats and horizontal porosity. The inner ceramic layer consists essentially of zirconia stabilized by about 6 to about 9 weight percent yttria. 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 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 each having a microstructure characterized by splats and horizontal porosity, 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, the outer ceramic layer having a thickness that is less than the thickness of the inner ceramic layer such that a ratio of the thickness of the outer ceramic layer to that of the inner ceramic layer is not greater than 0.5, and the outer ceramic layer having a porosity level that is lower than the porosity level of the inner ceramic layer as deposited, wherein the coating system has a thermal cycle life of at least 200 cycles when subjected to furnace cycle testing comprising one-hour cycles between about room temperature and about 1135 degrees C. with a dwell time of about forty-five minutes at peak temperature, the thermal cycle life ending when about 20% of the surface area of the coating system has spalled.