Materials Chemistry and Physics, Vol.176, 161-166, 2016
Microstructures, mechanical properties and corrosion resistance of the Zr-xTi (Ag) alloys for dental implant application
The Zr-xTi (Ag) alloys were designed for the application of dental implants. The microstructures of Zr-20Ti and Zr-40Ti alloy were observed using optical microscope and transmission electronic microscope. The hardness and compressive tests were performed to evaluate the mechanical properties of the Zr-xTi alloys. The electrochemical behavior of the Zr-xTi alloys with and without 6% Ag was investigated in the acidified artificial saliva containing 0.1% NaF (pH = 4). For comparison, the electrochemical behavior of cp Ti was examined in the same condition. The results show that the quenched Zr-20Ti and Zr-40Ti alloy exhibit acicular martensite microstructures containing twin substructure. They display good mechanical properties with the hardness of similar to 330HV, the yield strength of similar to 1000 MPa and the strain to fracture of similar to 25% at room temperature. Adding 6% Ag to Zr-20Ti alloy enhances the passivity breakdown potential and the self-corrosion potential, but hardly affects the corrosion current density and the impedance modulus. 6% Ag in Zr-40Ti alloy distinctly increases pitting corrosion resistance, which is attributed the formation of thick, dense and stable passive film under the joint action of titanium and silver. In comparison with cp Ti, Zr-40Ti-6Ag alloy possesses the same good corrosion resistance in the rigorous oral environment as well as the superior mechanical properties. (C) 2016 Elsevier B.V. All rights reserved.