I think the end product is a protective coating on a metal/alloy substrate via sol-gel or PVD that gives corrosion resistance and good surface finish. The sol-gel coating requires calcination. Therefore, interfacial bond strength and mechanical properties of the sol-gel coating may not be as good as that of PVD. On the flip side, PVD is more expensive than the sol-gel. Typically sol-gel technique is not used for corrosion protection coatings. It may be used for synthesizing ceramic particulate materials that can be applied as coating by other techniques. Thermal spray is a faster and economic method for protective coatings on large surfaces.

Dr Raja, thank you for your answer, from what I've seen sol gel has been used as coating for corrosion protection but like you've said it might not be that easy for the sintering/calcination needed.

thank you for your input.

Zakaria