EVALUATION OF EDDY-CURRENT AND BETA-BACKSCATTER TECHNIQUES FOR IN SITU MEASUREMENTS OF COMPLEX COATING THICKNESSES ON TURBINE ...

A RESEARCH AND DEVELOPMENT PROGRAM IS PROPOSED THAT WILL RESULT IN THE DEVELOPMENT OF A THICKNESS GAUGE FOR MEASURING THE THICKNESS OF CONDUCTIVE AND NONCONDUCTIVE COATINGS ON METAL SUBSTRATES. A DETAILED REVIEW AND EVALUATION OF COMMERCIAL SYSTEMS, THE TECHNICAL LITERATURE AND RESEARCH BEING CONDUCTED AT NATIONAL LABORATORIES AND UNIVERSITIES WILL BE CONDUCTED. THE PERFORMANCE OF THE IDENTIFIED COMMERCIAL SYSTEMS AND LABORATORY PROTOTYPES WILL BE ANALYZED IN VIEW OF THEIR CAPABILITY TO MEASURE THE THICKNESSES OF SEVERAL DIVERSE CONDUCTIVE AND NONCONDUCTIVE COATINGS ON CONDUCTIVE SUBSTRATES. ALSO, ANALYSES WILL BE PERFORMED TO DETERMINE WHICH OF THE MEASUREMENT TECHNIQUES IS OPTIMU FOR IN SITU COATING MEASUREMENTS ON VANES AND BLADES IN TURBINES. THE RESULTS OF THE SURVEY (REVIEW) AND ANALYSES WILL PROVIDE THE BASIS FOR THE TECHNIQUE RECOMMENDED FOR TESTING IN PHASE II AND THE DESIGN MODIFICATIONS OF SPECIFIC COMPONENTS NEEDED FOR IN SITU MEASUREMENTS OF COATING THICKNESSES IN TURBINES.