Industrial applications of nitriding methods with plasma ovens and ionic implantation for the treatment of steels used in car transmission systems

Abstract

The nitriding of metals is a process that makes it possible to alter the properties of surface hardness, wear, corrosion and heat resistance of the material. In order of importance, it is used in the treatment of ferrous metals, refractory metals, and, more recently, aluminum. The process of nitriding surfaces is applied, amongst others, in the mechanical, automobile and hydraulic industries, in the deformation of metals, foundries, steel making, biomedicine and foodstuffs. The process is used in the treatment of plastic injection molds, of automobile parts (valves, gears, pistons, etc.), aluminum extrusion molds, tools for the cutting and milling of metals, puncture of matrixes for cutting generally, treatment of prostheses, etc. In the last two decades, there has been progress in the technology used in the processes for treatment of surfaces, in particular with the development of the method of nitriding by plasma in a vacuum oven and methods of ionic implantation. Thermo-chemical treatment by plasma offers various advantages when compared with the traditional methods nitriding by salt bath or gaseous nitriding. Studies carried out recently, comparing the various methods of nitriding, show that it is possible to improve the metallurgical properties of the metals considerably, using implantation with a beam of ions and nitriding with intensified plasma. (AU)