Modeling of Nitrogen Penetration in Medical Grade CoCrMo Alloy during Plasma Nitriding

  • Arvaidas GALDIKAS Kaunas University of Technology, Lithuanian University of Health Sciences
  • Akvilė PETRAITIENĖ Kaunas University of Technology.
Keywords: CoCr alloy, nitriding, concentration dependant diffusion, trapping-detrapping model, kinetic modeling

Abstract

For analysis of plasma nitriding process and nitrogen penetration into CoCrMo alloy the trapping-detrapping model is applied. This model is commonly used for analysis of stainless steel nitriding, however, in this work it is shown that the same nitrogen penetration mechanism takes place in CoCrMo alloys. From the fitting of experimental curves, taken from literature, it is found by the proposed model that diffusion coefficient depends on nitrogen concentration according to Einstein-Smoluchowski relation D µ 1/CN. The diffusion coefficients for 400oC temperature nitriding of in CoCrMo are calculated. The shape of nitrogen depth profile curves are analyzed showing influence of different parameters such as detrapping activation energy, chromium concentration, etc.

DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3458

Published
2014-03-23
Section
METALS, ALLOYS, COATINGS