Author(s):
1. Dušan Petković, Faculty of Mechanical Engineering in Niš, Serbia
2. Goran Radenković, Faculty of Mechanical Engineering in Niš, Serbia
3. Vladislav Blagojević, Faculty of Mechanical Engineering in Niš, Serbia
4. Predrag Živković, Faculty of Mechanical Engineering in Niš, Serbia
5. Ivan Ćirić, Faculty of Mechanical Engineering in Niš, Serbia

Abstract:
Passivation of a biomedical grade 316L stainless steel by mean of nitric acid treatment was used to improve a protective oxide layer on the surface and to increase resistance to pitting corrosion in physiological solution. Both regression analysis and genetic algorithm were employed to reveal the effects of operating parameters of the nitric acid passivation (HNO3 concentration, temperature and passivation period) on the corrosion resistance of 316L stainless steel in Hank’s solution. The experiment designed as full factorial with three factors and three levels. The responses were the pitting potential values (Ep) obtained from potentiodynamic tests. Mathematical model was determined by using regression analysis. According to the model, the effects of each variable and interactions between them were calculated. Optimal intervals of the parameters were estimated by mean of genetic algorithm.

Key words:
stainless steel,passivation,nitric acid,regression analysis,genetic algorithm

Date of abstract submission:
14.02.2013.

Conference:
DEMI 2013

Applied paper from author