12A Matthews and HD Sundquist in Proc Int Ion Engineering Congress ISIAT 83 T Takagi Ed IEE Japan 1983 p 1311

13. R. Weil and K. Sheppard,Mater. Char., Vol 28, 1992, p 103-112 Microstructure/Property Relationships

In the preceding section, it was shown that although the same coating materials can be deposited by a number of different processes, the tructure of the coatings produced will be very different. Whereas a very fine equiaxed grain structure is produced by electrodeposition, a columnar structure is produced by vapor-deposition processes (grain boundaries perpendicular to the interface), and a splat structure is produced by plasma spraying (splat boundaries parallel to the interface). Thus, it should be intuitive that the coatings will not have the same properties, and this is what is observed in practice. Considerable attention should be paid to the microstructure of the coating if performance is to be understood. There are numerous techniques that can provide relevant information.

Structure/property relationships have been determined empirically for many deposition processes for a restricted range of coating materials (e.g., Ref 13, 14). However, theoretical modeling of coating properties based on microstructure is not well advanced. A characterization of the structures and properties of commercially available coatings produced by different deposition technologies is often necessary to aid in coating selection and specification. Because some control of coating structure is possible for most deposition technologies, optimizing the microstructure of the coating for a given application is also a possibility. Structural characterization is a necessary step in achieving this rather ambitious goal.

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