골내 고정 장치용 초내식성 오스테나이트 및 듀플렉스 스테인리스강 가공재의 특성

Abstract

Nickel is one of the most common causes of allergic contact dermatitis and hypersensitivity. In case of stainless steel as biomaterials, the higher the corrosion resistance and the lower the nickel content, the better it is for the human body. However, because nickel plays an essential role in the stabilization of the austenitic phase and the corrosion resistance of stainless steel, it is difficult to remove the nickel from the constituents of stainless steels completely. Therefore, the purpose of this study was to investigate corrosion resistance, cytotoxictiy, and mechanical property of super stainless steels, which had high corrosion resistance by synergistic effect of Mo(or W) and N, with respect to nickel content and to evaluate their potential for orthodontic applications. Super austenitic stainless steel(SR-50A) had high nickel content of 22% and super duplex stainless steels nickel contents of 6∼10%. Super austenitic and duplex stainless steels had nitrogen contents of above 0.2%. Also, these steels had high Mo or W contents which were able to increase the localized corrosion resistance. In terms of hardness, super stainless steels, which had Vickers hardness values of 374∼400 Hv in cold-rolled state and 186∼285 Hv in annealed state, exhibited higher values than 316L S. S. Duplex stainless steels exhibited higher mechanical properties than austenitic stainless steels. In terms of corrosion resistance, super stainless steels exhibited lower passive current dentistry(2.3∼3.8 ㎂/㎠) than pure Ti(6.6㎂/㎠) in the body-simulated solution and similar potentiodynamic polarization behaviors. Pitting corrosion occurred in 316L S. S. but not in the others. Thus these steels were considered to have high corrosion resistance in the human body. In terms of cytotoxicity, SR-50A and SAF2507 exhibited none cytotoxicity and the others slight. This results indicated that the cytotoxicity of alloys containing nickel had no relation with nickel content because SR-50A with the highest nickel content exhibited none cytotoxicity. In conclusion, it si considered that super stainless steels with high corrosion resistance and good biocompatibility can be used for orthodontic applications because of the enhanced passive film by high addition of Mo, W, N, etc.