Sputter-ion plating of coatings for protection of gas-turbine blades against high-temperature oxidation and corrosion

Considerable effort is being devoted to the development of overlay coatings for protecting critical components such as turbine blades against high-temperature oxidation, corrosion, and erosion damage in service. The most commercially advanced methods for depositing coatings are electron-beam evaporation and plasma spraying. Sputter-ion plating (SIP) offers a potentially cheaper and simpler alternative method for depositing overlays. Experimental work on SIP of Co-Cr-Al-Y and Ni-Cr-Al-Ti alloy coatings is described. Results are presented of metallographic assessment of these coatings, and of the results obtained from high-velocity testing using a gas-turbine simulator rig.