생체용 Ti-xNb-ySi합금의 미세조직 및 전기화학적 특성

Abstract

As biomedical metal materials implanted directly in human body, for the purpose of developing Ti alloys which are excellent at corrosion resistance, biological stability and biocompatibility in human body, moreover, similar to human body in mechanical dynamic properties, I studied by adding Nb, Si to Ti respectively that are biologically stable element. In order to investigate the microstructure and electrochemical properties of biomedical Ti-xNb-ySi alloys were melted by using a vacuum furnace(vacuum arc melting system. SVT, KOREA) and then homogenized for 24hr at 1050 ℃. The samples were cut and polished for microstructure and corrosion test. The microstructures were conducted by using optical microscope(OM) and scanning electron microscope(SEM). The corrosion behaviors were investigated using potentiosat(EG&G Co, 263A) in 0.9% NaCl solution at 36.5±1℃ As Nb was increased by 20 %, 40 % respectively at the Ti-Nb-Si alloy, α + β phase and β phase were molded. As a result of X-ray diffractometry analysis, the peak of matrix β phase was appeared high, and it could be confirmed that there is a peak of α-martensite phase, which the strength is low relatively. In addition a (30)face peak of ω phase could be confirmed at Ti-20Nb-0.2Si alloy, but ,when Nb content was increased, the peak of ω phase wasn't observed. A value of hardness was measured that α + β type Ti-20Nb alloy was 457 HV and β type Ti-40Nb alloy was 312 HV on the average according to the investigation of electrochemical corrosion behaviors at 36.5±1 ℃, 0.9 % NaCl electrolyte, the more Nb content increased, the more corrosion resistance increased, and β phase Ti-Nb alloy is more better in the part of corrosion resistance than α + β phase.