PENGARUH PENAMBAHAN MOLIBDENUM TERHADAP MORFOLOGI STRUKTUR MIKRO, SIFAT MEKANIK DAN KETAHANAN KOROSI PADUAN Zr-Nb UNTUK MATERIAL IMPLAN

Abstract

INFLUENCE OF MOLIBDENUM ON MICROSTRUCTURE CHARACTERISTIC, MECHANICAL PROPERTIES AND CORROSION RESISTANCE OF Zr-Nb ALLOY FOR IMPLANT MATERIAL. Zr-Nb alloy is an alloy that widely used for bio-implants. The addition of other elements in the Zr-Nb-based alloys such as molybdenum will increase the mechanical properties and corrosion resistance. This research was conducted with the aimed to observe the characteristic of morphology of the microstructure, mechanical properties and corrosion resistance of the Zr-Nb alloys with and without molybdenum addition. The composition of the alloy was Zr-2.5 wt.% Nb and Zr-2.5 wt.% Nb-0.5 wt.% Mo, where molybdenum was added to the alloy in the melting process using an electric arc furnace. Ingot of Zr-2.5 wt.% Nb and Zr-2.5 wt.% Nb-0.5 wt.% Mo alloys were then tested in Vickers micro hardness, metallographic with optical microscopy (OM) and SEM (scanning electron microscopy), XRD (X -ray diffraction) and environmental corrosion test in simulated body fluid (SBF). Results showed that the structure of α-Zr phase was formed and distributed homogeneously in fine-grain. The corrosion rate of the Zr-2.5 wt.% Nb alloy was 0.1023 mpy, whereas after the addition of molybdenum the corrosion rate of Zr-2.5 wt.% Nb-0.5 wt.% Mo alloy was decreased to 0.089 mpy. This occurred due to the formation of a thin layer of zirconium and molybdenum oxide as surface protection. The hardness of Zr-2.5 wt.% Nb alloy reached 183 VHN and increased to 230 VHN after the addition of 0.5 wt.% Mo. The phenomenon of grain refinement resulting in high dislocation density in the alloy of Zr-2.5 wt.% Nb-0.5 wt.% Mo.