To provide processing for preventing free sulfur useful for segregation on a substrate surface from existing by eliminating the sulfur from a bulk substrate material before forming a coating or adding a small percent of a sulfide forming agent (for example, yttrium or hafnium) to the substrate material.

In the method for forming a barrier layer of a specific reactive element on the surface of the substrate material, the substrate material is <1 ppm free sulfur segregable on the surface of the substrate material and the specific reactive element and its nitride, carbide and oxide further contain less stable elements than the corresponding nitride, carbide and oxide of the specific reactive element. The method includes the process of forming the barrier layer of the nitride, carbide and oxide.