Effect of artificial aging conditions on corrosion resistance of a TiNi alloy

The present paper is focused on three different aging treatment of a TiNi alloy in order to enhance corrosion resistance in oral cavity environment. The best corrosion resistance in artificial saliva after aging treatment was found in the case of sample which was heat treated at 700 °C/20 min/water cooled, followed by aging at 400 °C/1.5 h/water cooled. Subsequent to such a heat treatment, the EDX surface analysis indicated an increase of Ti content of the matrix. This effect is in connection with stable and metastable precipitates which appear during the aging. Also, based on the greater affinity to oxygen of Ti compared to Ni, a uniform Ti based oxide layer is predominant explaining the better electrochemical stability. The obtained precipitates morphology is also an important factor in the corrosion behavior.