Bio-corrosion study on zirconium-based bulk-metallic glasses

Bio-corrosion behaviors of Zr55Al10Cu30Ni5 and (Zr55Al10Cu30Ni5)99Y1 (at.%) BMGs in a physiologically relevant environment were investigated and compared to those of standard, crystalline biomaterials. The effect of 1 at.% yttrium addition on the corrosion resistance of the Zr55Al10Cu30Ni5 BMG was determined. Cyclic-anodic polarization tests were performed at 37 °C in a phosphate-buffered saline (PBS) electrolyte aerated with a 4 vol.% O2/N2 gas mixture. Surface morphologies after electrochemical studies were observed by the scanning-electron microscopy (SEM). Compositions of corrosion products were investigated by the energy dispersive X-ray (EDX) to identify the corrosion mechanism. It was found that (Zr55Al10Cu30Ni5)99Y1 BMGs exhibited a superior bio-corrosion resistance with a corrosion-penetration rate (CPR) comparable to those standard, crystalline biomaterials, while Zr55Al10Cu30Ni5 BMGs exhibited a lower bio-corrosion resistance. Possible mechanisms for the beneficial effect of the Y addition are proposed that the structure of the passive film was changed, and/or the formation of the passive film was accelerated.