DIFFUSION BARRIER LAYERS

摘要

A method of applying a continuous stable intermetallic diffusion barrier lay er to a high temperature metallic article is described. In many instances, protective coatings are incompatible with the material of th e substrate to which they are applied. Such incompatilibility is overcome in the invention through in situ formation of an intermediate stabl e diffusion barrier layer by sequential deposition and subsequent reaction of suitable metals to form a continuous intermetallic layer. A conventional overlay coating may then be applied to the intermetallic layer without risk to the underlying substrate. The invention also contemplates creation of unitary diffusion barriers from multi-layer deposits; deposition of plural diffusion barriers, and formation of complete protective systems comprising substrate, diffusion barrier(s) and overlay coating prior to heat treatment in situ.