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Coatings continue to be used on steel compressor components to maximize component life and compressor efficiency. Aluminum-ceramic coatings have been used on steel compressor components for a quarter of a century. During this time, coating application processes have been continually refined for improved performance. These processes are reviewed and a new process included - SermeTel Process 5380 DP. In this process, both coating material and process changes are made to produce finished coatings having improved surface finish, corrosion resistance and erosion properties. Test data is presented for comparison with earlier coating systems. For over twenty-five years, metallic-ceramic coatings have been successfully used on steel components of turbine engines to combat corrosion and erosion. The basic coating of this type, SermeTel W®, continues to be used in a variety of applications and is a base line from which new and improved coating systems can be compared.

Corrosion of the steel compressor disks of gas turbines is a serious problem. In this study, the causes of disk corrosion failure are reviewed; recommended protective coatings and lubricant films are described, and their interactions noted. To evaluate these corrosion resistant coatings, five candidate coatings are described as well as three lubricant/antigallant films commonly used on disks or on blade roots in contact with disks. Results of comparative testing in environmental tests are described for the protective coatings with and without the presence of lubricant films. Data is presented graphically; optical and SEM photomicrographs are included. It is shown that lubricants/antigallants can seriously degrade the performance of all protective coating systems unless great care is taken in selection. Further it is shown that sealed metallic/ceramic coatings provide superior corrosion protection when compared to other coating systems.