Process for depositing a coating on a blisk

A process of depositing an erosion-resistant ceramic coating on a blisk of a gas turbine engine, the blisk comprising a disk with integral blades that radially extend from the disk relative to an axis of rotation of the blisk, the blades and disk having flowpath surfaces, the flowpath surfaces of the blades comprising convex flowpath surfaces and oppositely-disposed concave flowpath surfaces that are more susceptible to erosion from collisions with particles than the convex flowpath surfaces during operation of the blisk within the gas turbine engine, the processing comprising:

• placing the blisk adjacent a coating material source in a physical vapor deposition apparatus configured to evaporate the coating material source and generate coating material vapors;
• orienting the blisk relative to the coating material source so that the axis of rotation of the blisk is approximately parallel to a linear path that the coating material vapors flow from the coating material source to the blisk, and the concave flowpath surfaces of the blades face the coating material source;
• and
• rotating the blisk about the axis of rotation thereof and evaporating the coating material source to preferentially deposit the coating material vapors and form an erosion-resistant ceramic coating on the concave flowpath surfaces of the blades.