열산화 처리에 따른 Ti-Ag 합금의 표면 특성

Abstract

Thermally oxidized Ti-Ag alloys, cp-Ti and Ti-A14V was investigated to find the proper heat treatment temperature and heat treatment duration for dental application. Surface microtopology by SEM showed oxide particles formed on all specimens treated at 600℃ and coarse, fully-crystallized lumps on specimens treated at 800℃. In macroscopic roughness measurement, Ra ranged from 0.083 to 0.29 }μm resulting from scratching by #600 emery paper; for non-contact method, from 0.34 to 2.84 nm resulting from the contour by oxide crystals on and between the ridges. The thicknesses of oxide layers were presumed to range from 100 to 250, 250 to 700, and over 1700 A for specimens treated at 400, 600, and 800℃, respectively. Oxide layers separated from the matrices on the cross sections of specimens atmosphere cooled after heat-treated at 800℃, which was not observed on those treated at 600℃. Oxidation behaviors of Ti-Ag alloys were observed to be similar to those of cp-Ti specimens by XRD analyses: TiO2 growth on surfaces followed by coexistence with Ti203`s as treatment temperature increased; TiO growth followed by spread of both rutiles and Ti203`s with temperature increase on specimens treated for 4 hours. Alumina was detected on Ti6A14V specimens, where microgaps between layers of alumina and titania considerably reduced the adhesive force of tinania layers on matrices. Conclusively, heat treatment temperature was more significant than treatment duration and the most desirable temperature was determined to be 600℃.