|About this Abstract
||Materials Science & Technology 2012
||Surface Protection for Enhanced Materials Performance: Science, Technology and Applications
||Effectiveness of Trending Citric Acid Passivation vs. Nitric Acid Passivation on CoCrMo
||Sophie Xiaofan Yang, Bernice Aboud
|On-Site Speaker (Planned)
||Sophie Xiaofan Yang
Both citric acid (CA) passivation and nitric acid (NA) passivation are widely used in the medical device industry. To evaluate effectiveness of trending CA passivation vs. NA passivation on CoCrMo, 2 factor- 2 level Design of Experiments based on ASTM A 967 was designed to challenge acid concentration and temperature. XPS analysis showed chromium oxide, a corrosion inhibitor, in the passive film increased 20 at% after CA or NA passivation. XPS depth profile showed a thicker passive film after NA passivation compared to CA passivation. ICP-MS analysis showed lower ion release from CoCrMo by 30 wt% after NA passivation, while the alloy subjected to CA passivation showed <10 wt% reduction. The roles of citric acid and nitric acid in passivation are also discussed.