Abstract: A nitrided metal includes a metal core with a first microstructure and a nitrogen-containing solid solution region on the metal core. The nitrogen-containing solid solution region is free of nitride compounds and includes a second microstructure which is equivalent to the first microstructure. The first microstructure and the second microstructure are a tetragonal crystal structure.

Abstract: A surface processing method and power transmission component includes transforming a surface region of a metal alloy into a hardened surface region at a temperature that is less than a heat treating temperature of the metal alloy. The metal alloy includes about 11.1 wt % Ni, about 13.4 wt % Co, about 3.0 wt % Cr, about 0.2 wt % C, and about 1.2 wt % Mo which reacts with the C to form a metal carbide precipitate of the form M2C. The surface processing temperature, vacuum pressure, precursor gas flow and ratio, and time of processing are controlled to provide a desirable hardened surface region having a gradual transition in nitrogen concentration.

Abstract: A method of nitriding a metal includes transforming a surface region of a generally nitrogen-free metal into a nitrogen-containing solid solution surface region. A first heating process heats the surface region at a first temperature in the presence of a nitrogen gas partial pressure to form a nitrogen-charged surface portion on the surface region. A second heating process heats the surface region and nitrogen-charged surface portion at a second temperature for a predetermined time to interstitially diffuse nitrogen from the nitrogen-charged surface portion a depth into the surface region. Coincident with the second heating process, an ionized inert or reducing gas removes the nitrogen-charged surface portion. The resulting nitrogen-containing solid solution surface region has a gradual transition in nitrogen concentration.

Abstract: A method of nitriding a metal includes transforming a surface region of a generally nitrogen-free metal into a nitrogen-containing solid solution surface region. A first heating process heats the surface region at a first temperature in the presence of a nitrogen gas partial pressure to form a nitrogen-charged surface portion on the surface region. A second heating process heats the surface region and nitrogen-charged surface portion at a second temperature for a predetermined time to interstitially diffuse nitrogen from the nitrogen-charged surface portion a depth into the surface region. Coincident with the second heating process, an ionized inert or reducing gas removes the nitrogen-charged surface portion. The resulting nitrogen-containing solid solution surface region has a gradual transition in nitrogen concentration.

Abstract: A method of surface refinement for refining a first roughness of a surface of a component to a second roughness. The method includes wetting the first roughness surface with an aqueous mixture that includes solid media. The aqueous mixture chemically alters the surface forming a chemically converted surface. Relative movement between the chemically converted surface and the solid media produces the refined second roughness.

Abstract: A surface processing method and power transmission component includes refining a surface region of a metal from a first roughness to a second roughness less than the first roughness. A solid lubricous coating or a hard coating is then deposited on the surface region. The metal has a surface hardness above 50 Rc to reduce the risk that the metal will deform under the coating and leave the coating unsupported. The surface region of the metal may be transformed into a nitrogen-containing compound or solid solution surface region before the surface refining step and deposition of the coating.