Role of carbon and nitrogen in the improvement of corrosion resistance of new powder metallurgy Co-Cr-Mo alloys

Abstract

Microstructural changes that result in relevant improvements in mechanical properties and electrochemical behavior can be induced by the use of different sintering conditions of ASTM F75 Cobalt alloys during their processing through powder metallurgy technique. It has been observed that the increase in carbon and nitrogen content improves corrosion resistance and mechanical properties as long as the precipitation of carbides and nitrides is avoided thanks to the use of rapid cooling in water after the sintering stage. In addition, the reduction of the particle size of the powder improves the hardness and resistance to corrosion in both acid media with chlorides and phosphate buffer medium that simulates the physiological conditions for its use as a biomaterial. These results lead to increased knowledge of the role of the carbon and nitrogen content in the behavior displayed by the different alloys studied.