A coating for a mold surface of a casting mold includes a metallic bond coat bonded to the mold surface and having a continuous, uniform thickness of between about 0.002 to 0.005 inch on the mold surface. A topcoat of yttria stabilized zirconia is located on top of the metallic bond coat and has a continuous, uniform thickness of between about 0.005 to 0.030 inch. The topcoat has a porosity between 5-15%. The topcoat has a surface layer having a thickness of between about 0.001 to 0.002 inch and a porosity of less than 1%.