SPECIFYING EB-PVD PROCESS PARAMETERS FOR COATING OF A SECOND STAGE TURBINE BLADE USING AN EXPERIMENTALLY VERIFIED CAD MODEL OF THE PROCESS

摘要

A model was developed to predict the thickness of the thermal barrier coating (TBC) applied to specific points on a rotating PW4000 second stage turbine blade using electron beam physical vapor deposition (EB-PVD). The theoretical model of coating deposition rates as a function of position in the PVD vapor cloud (Knudsen cosine law) was experimentally verified. The experimental work consisted of a series of four turbine blades coated under various coating conditions. Based on the verified model, a UniGraphics (UG) CAD model of the process was built. A UG User Function (UFunc) was programmed to predict coating thickness for a wide variety of EB-PVD process parameters to populate a database of contoured coating profiles. A software tool was then developed to specify the manufacturing process parameters to fabricate a contoured EB-PVD TBC of partially stabilized zirconia. A coating profile matching routine was included in the software to identify the process parameters closest to the desired coating profile. The focus of this paper is on the experimental methods, the CAD model and the software tool.