A COMPARISON OF THE CORROSION BEHAVIOR AND SURFACE CHARACTERISTICS OFVACUUM-BRAZED AND HEAT-TREATED TI6AL4V ALLOY

The corrosion characteristics of the brazed Ti6Al4V specimens were ana lysed and compared with respect to the conventionally heat-treated spe cimens by an electrochemical corrosion test. The object of this resear ch was to explore the potentiality of the brazed titanium for biomater ials. The characteristics of the 1300 degrees C heat-treated and the 9 70 degrees C brazed specimens, with passivation and sterilization trea tment, were evaluated by measurement of corrosion potential, E-corr, c orrosion current densities, I-corr, polarization resistance of the rea cted surface films, R-p, in a potentiodynamic test. The experimental r esults show that the corrosion rates of the heat-treated and the braze d samples are similar at E-corr, and the value of E-corr for the braze d sample is noble to the heat-treated samples. The passive current den sity of the brazed specimen is either lower or higher than the heat-tr eated specimen, depending on the polarization potential. By Auger elec tron spectroscopic and high-resolution X-ray photoelectron spectroscop ic analysis on specimens from the potentiostatic test, the elements of copper and nickel in the brazing filler were not detected while less alu mina was found in the reacted film of the brazed specimens when co mpared with the heat-treated specimens. The implication of the results is discussed.