Method for forming a pack cementation coating on a metal surface by a coating tape

Abstract

A pack cementation coating tape such as a nickel aluminide coating tape includes a reactive metal such as aluminum, a filler such as aluminum oxide, and a halogen carrier such as ammonium chloride held together by fibrillated polytetrafluoroethylene. The tape is useful in coating localized areas of nickel containing alloys to provide a nickel aluminide surface coating. The coating is formed by positioning the tape over the metal surface and heating the tape to a temperature of about 1250.degree. F. wherein the element metal such as aluminum reacts with the halogen carrier and in turn reacts with nickel on the surface of the nickel alloy to form the nickel aluminide coating. A masking tape formed from a separating layer, a brazing alloy layer and a nickel layer can be used to mask localized portions of the surface to prevent coating at these areas.

Dependencies are inferred from the claim text.