Compressor Disk Corrosion: Problems and Solutions

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.