What is Hardfacing?

If you go here first;

Hardfacing - Wikipedia, the free encyclopedia

Then you might be able to ask intelligent questions on the subject.

"Please distinguish between cladding and overlay". Please give us your understanding of cladding and overlay, so we'll know how to answer.

Yes, there is a variety of fusion sprayed hard coatings, (facings.). All depends what you need it for, which you do not mention, naturally.

There are companies that specialize in "hard facing" and utilize plasma deposition of hot gas vapors or hot gas streams to deposit stellite, boron nitrides and the like. Spray deposition and even hard chrome plating are methods. Try Googling some

And one of my Valve Vendors tells me he cannot supply as scheduled due to a dire lack or shortage of boron in the world and now cannot provide tungsten carbide trim for the valves. I asked him about stellite and hardfacing and was talked to in circles for about 15 minutes. lol.