The present invention provides a method for manufacturing a finished metal object or product having a corrosion resistant layer integral to or within a top portion of at least one of its surfaces that would be exposed to a corrosive environment. In one embodiment, the method for manufacturing is directed to a finished metal tubing product having a corrosion resistant layer within its inside surface that is exposed to a fluid and wherein the corrosion resistant layer is a zinc-metal oxide layer, such as a zinc-chromium oxide layer, or a zinc-mixed metal oxide layer. In addition to methods of manufacturing, the present invention provides finished metal objects or products having a corrosion resistant layer integral to or within a top portion of at least one surfaces that would be exposed to a corrosive environment.

Unique and improved chromizing processes are disclosed. The processes involve forming localized chromizing coatings onto selected regions of a substrate. The chromium diffusion coatings are locally applied to selected regions of substrates in a controlled manner, in comparison to conventional chromizing processes, and further in a manner that produces less material waste and does not require masking. A second coating can be selectively applied onto other regions of the substrate.

Unique and improved chromizing processes are disclosed. The processes involve forming localized chromizing coatings onto selected regions of a substrate. The chromium diffusion coatings are locally applied to selected regions of substrates in a controlled manner, in comparison to conventional chromizing processes, and further in a manner that produces less material waste and does not require masking. A second coating can be selectively applied onto other regions of the substrate.