A casting process for producing metal alloy castings, facecoats and apparatuses suitable for carrying out the process, and castings produced by the process. The casting process entails the use of a mold having a cavity with a continuous aluminum-containing solid facecoat on its surface. A molten quantity of a metal alloy is introduced into the mold cavity so that the molten alloy contacts the solid facecoat. The mold is then allowed to cool to solidify the molten alloy and form a cast product. During the casting process, aluminum in the solid facecoat diffuses into the cast product to form an aluminum-containing surface region at the casting surface. Following removal of the cast product from the mold, an alumina-containing scale grows on the casting surface as a result of oxidation of the casting surface region.