a gas turbine component with a layer of ceramic material defining a wear surface , in which an array of cross - shaped depressions formed in the wear surface define a continuous labyrinth of orthogonal walls of the ceramic material , and reduce the area of the wear surface by about 50 %. within a representative area of the wear surface , the depressions provide a ratio of a lineal sum of depression perimeters divided by the representative area of the wear surface of least 0 . 9 per unit of measurement for improved abradability characteristics of the wear surface .