Gas phase and surface modelling of nitriding afterglow plasmas

A mathematical model has therefore been developed in order to gain a better understanding of the phenomena concerned, with a view to improving the design of industrial nitriding plant. The approach employed involved the following steps : study of the behaviour of the reactive species in a post-discharge treatment furnace; a sub-model based on the equations of conservation of momentum, mass and heat, enabling calculation of the concentration of reactive species in the post-discharge zone; a sub-model describing nitrogen diffusion in the solid; experimental measurements to validate the model; predictive use of the model to determine the effects of the principal process parameters (geometrical and operating parameters)