Patent ID: 6884476
Filing Date: 2005-04-26
Classification: C23C,Y02T

Abstract:
1. A method for applying an environmental coating to predetermined areas of a superalloy component having internal passageways, comprising the steps of: preselecting first surfaces of the superalloy component; applying a ceramic material to form a ceramic layer over the preselected first surfaces of the superalloy component while leaving remaining surfaces of the superalloy component exposed and without obstructing the internal passageways, the ceramic material forming a substantially crack-free, continuous layer bonded to the preselected first surfaces, the layer being stable at temperatures above about 1400° F. without substantially reacting with the first surfaces of the superalloy component, the component having exposed predetermined surfaces and protected preselected first surfaces layered with ceramic material; applying an environmental coating to the exposed predetermined surfaces of the superalloy component by flowing gaseous vapors of an environmental coating composition over the surfaces of the component at temperatures above about 1400° F. for a time sufficient to achieve a predetermined coating thickness on the exposed predetermined surfaces, the ceramic layer applied over the preselected first surfaces of the component preventing a reaction between the gaseous vapors and the preselected first surfaces; then completely removing the ceramic layer from the preselected first surfaces of the superalloy component, thereby exposing the protected preselected first surfaces of the component underlying the ceramic layer, the protected preselected first surfaces being substantially free from the environmental coating composition while the predetermined surfaces include an environmental coating of predetermined thickness formed by reaction of the gaseous vapors and the exposed predetermined surfaces.