Investigation The Effect of Tellurium Addition on Corrosion Resistance of Ti6Al4V alloy

Abstract

The purpose of this study is to investigate the impact of Tellurium alloying element (0,5, 1, 1,5, 2, 2,5, 3, 3,5, 4, 4,5 and 5 wt%) on corrosion resistance of Ti6Al4V alloy in Hank and saliva solutions. All alloys have been prepared by powder metallurgy technique, the compact pressure was determined as 800MP and the green samples sintered at 350 C0 for 1h then at 550 C0 for 1h and at 1000 C0 for 2 h in inert gas (of Argon), then the samples cooled in the furnace to room temperature. The microstructure was observed using a light optical microscope and has shown that all specimens of alloys contain two regions: the α-Ti phase and the β-Ti phase. Generally, compared with the base alloy, the addition of the Te element leads to an increase in the α-phase due to the effect of Te as the α stabilizer element. Electrochemical tests (potentiodynamic polarization and OCP – Time measurement) in Hank's and saliva solutions were used to evaluate corrosion resistance of Ti6Al4V alloy. When tellurium was added, the OCP shifted to the positive direction. This makes the alloy more noble and increases its resistance to corrosion by decreasing corrosion current density. The percentage of improvement ranges from 2,50 % to 61,92 % in saliva solution and from  16,27 % to 88,32 % in Hank's solution. For both solutions, the best percentage of improvement is 5 % Te