Effect of Tungsten additions on Microstructure and Corrosion resistance of F75 alloy.

Abstract

For many surgical applications such as knee implant, metal-to-metal Hip jointing and denta implants, CoCrMo allays are the main choice. The present study aims to study the effect of Tungsten on Microstructure and Corrosion resistance of CoCrMo (F75) alloy. Tungsten has been added to the base alloy in various weight ratios (0.5, 1 and 1.5 wt. percent). The alloys have been made using powder metallurgywhich has been sintered with two stages at 500°C (2 h) and 850°C (6 h) under Argon atmosphereMicrostructures observation, Corrosion resistance, open circuit potential and Brinell macro-hardness, have been performed. In the microstructure test this phase (CoCr and CoCrMo) was appeared. Corrosion test results have shown that with the addition of (1,5% W) the highest corrosion resistance was found, which gives the lowest rate of corrosion (4.310 mpy) in Ringer's solution. The hardness of F75 alloy improve after the addition of tungsten in Ringer's solution, Also hardness increases as tungsten additives increase, which have the highest percentage (1.5%W) gave the highest hardnes