PROCESS-CONTROL OF PLASMA NITRIDING AND PLASMA NITROCARBURIZING IN INDUSTRY

Whenever plasma processes are used under continuous production conditions to produce nitrided or nitrocarburized layers, a variety of parameters has to be controlled in order to guarantee consistency of quality. Some of these parameters must be considered during the engineering period of an installation. It is shown that a minimum power density is reqUiTed independently of the applied frequency to achieve saturation of the surface with nitrogen. Computer simulation demonstrates the influence of the effective wall temperature on the power density and temperature uniformity. Compound layers with and without porosity can be obtained using different gas compositions. Additionally, iron oxide layers can be produced in a plasma on top of a compound layer. A microprocessor system with special software is presented which fulfils the requirements of modern statistically controlled production.