Effect of ball milling time on corrosion and wear resistance of Ti-13Nb-5Sn dental alloys

Ti-13Nb-5Sn dental alloy was prepared by powder metallurgy method. The effects of ball milling time (3, 12, 24 h and 48 h) on powder performances, material microstructure, electrochemical corrosion and tribological behavior were investigated. The results show that with the increase of ball milling time from 3 h to 48 h, the powder morphology gradually changes from bulky to fine particles, and a part of Nb and Sn atoms diffuse into Ti lattice to form a certain volume of Ti(Nb) and Ti(NbSn) solid solutions. Moreover, equiaxed α-Ti decreases and shifts into columnar grain boundary α-Ti, and the basket structure changes to Widmandelsteiner structure. The potentiodynamic polarization curves show that the corrosion potential (Ecorr) and polarization resistance (Rp) of the alloy display an upward trend, the corrosion current density (Icorr) reveals a downward trend in artificial saliva (AS) and simulated body fluid (SBF). The corrosion resistance of the alloy is improved because of reduction of α-Ti and increase of β-Ti. The hardness of the alloy increases, while the friction coefficient, wear depth and wear rate gradually decrease. More grain boundaries generate in sintering of the fine powder, resulting in the wear resistance of the alloy intensifying. The Ti-13Nb-5Sn alloy prepared by mechanical alloying combined with molding and sintering shows good corrosion and wear resistances, and has a great potential in the dental field.