US Patent 10494945 Outer airseal abradable rub strip

A blade outer airseal has a body comprising: an inner diameter (ID) surface; an outer diameter (OD) surface; a leading end; and a trailing end. The airseal body has a metallic substrate and a coating system atop the substrate along at least a portion of the inner diameter surface. At least over a first area of the inner diameter surface, the coating system comprises an abradable layer system comprising a plurality of layers including a relatively erosion-resistant first layer atop a relatively abradable second layer.