Modifying the properties of the Inconel 625 nickel alloy by glow discharge assisted nitriding

The nickel alloys of the Inconel type (containing above 15wt% of chromium), used in many industrial applications including the manufacture of aircraft, chemistry, power generation, and material processing, have advantageous mechanical properties, high plasticity and good corrosion resistance, but their frictional wear resistance is poor. This drawback can be obviated by subjecting the alloys to various surface treatments.The paper describes the structure and properties of nitrided layers produced on the Inconel 625 nickel alloy (20wt%Cr, 10wt%Mo, 5wt%Fe, 1wt%Co, balance-Ni). It has been found that the diffusion-type chromium nitride layer produced on the alloy surface improves the hardness, frictional wear resistance, fatigue strength and corrosion resistance of the alloy. It was demonstrated that the nitriding process can be successfully used for prolonging the service life of the fiberizing disc intended for the fabrication of what is known as glass wool.