A method of bias power density control in the ASPN-process

摘要

In the present work, a new concept of in-situ estimation of the load surface area implemented in the active screen plasma nitriding (ASPN) process is proposed. The method is based on the correlation between the load surface area and the plasma conductivity derived from the linear slope of the current-voltage discharge characteristics, which was obtained during the variation of the bias power applied to the workload. A series of tests with defined load sizes provides a linear dependency which is proposed to be used for a future estimation of the surface area of any load with unknown size. A process window has been defined with respect to the load size and the bias power density applied to the components' surface to achieve acceptable nitriding results in an industrial scale ASPN-system.