Patent ID: 8714233
Filing Date: 2014-05-06
Classification: B22C,B22D,C23C

Abstract:
1. A process for producing a cast product from a metal alloy, the process comprising: providing a mold with a cavity and a continuous solid facecoat on a mold surface within the cavity, the solid facecoat comprising at least 15 weight percent of a powder containing metallic aluminum and an activator; introducing a molten quantity of the metal alloy into the cavity of the mold so that the molten metal alloy contacts the solid facecoat and the activator vaporizes and reacts with the metallic aluminum in the solid facecoat to form a volatile aluminum compound; cooling the mold to cool and solidify the molten quantity of the metal alloy and form a cast product of the metal alloy, during which at least a portion of the volatile aluminum compound reacts at the surface of the molten quantity of the alloy and/or the cast product contacting the solid facecoat to infuse the metallic aluminum into a surface of the cast product to form an aluminum-containing surface region in the cast product; removing the cast product from the mold; and then growing a scale on the surface of the cast product as a result of oxidation of the surface region of the cast product, the scale comprising alumina as a result of oxidation of aluminum in the surface region of the cast product.