The effects of encapsulation methods on thermally sprayed coatings

There are a wide variety of thermally sprayed coatings being utilized for many different applications. If the microstructural characteristics of these coatings is to be accurately evaluated, proper metallographic techniques need to be implemented. Conflicting information pertaining to the integrity of the coating will be produced if incorrect metallographic practices are used. Every step in the preparation process must be properly performed so as not to create coating damage that cannot be removed during subsequent operations. There is a concern in the thermal spray industry pertaining to the proper encapsulation methods for specific coatings. A study was conducted using a series of functionally graded coatings consisting of varying amounts of NiCoCrAlY and PSZ (zirconia) specifically evaluating thermosetting and castable epoxy encapsulation methods and the effect these methods have on the coating characteristics. Each encapsulation procedure affected the coatings differently, and the observable differences were discussed in this paper.