Abstract: A process for diffusion bonding a coating of Nitinol intermetallic compound to a surface of a metallic substrate includes heating and cleaning the surface of the substrate to a metallurgically clean condition by creating a plasma arc in a plasmatron and partially ionizing and heating a stream of inert gas in the plasma arc. The stream of partially ionized gas from the plasmatron is directed to the surface of the substrate to remove oxides and other contaminants from the surface. Nitinol powder is entrained in a mixture of hydrogen and argon gasses heated and ionized in the plasmatron, thereby heating the powder to a partially molten state. The partially molten power is ejected in the gas mixture from the plasmatron at high velocity and impacts against the metallurgically clean heated substrate surface to produce a diffusion bond between the Nitinol intermetallic compound and the metal substrate.