http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김교한,허만수,김형일,황운석,高田 雄京,奧野 攻 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4
One of the fields in which titanium(Ti) is becoming increasingly valuable is the field of biomaterials. Ti had shown its good corrosion resistance, high strength to weight ratio, and compatibility with human tissues. Such applications of Ti in this area involve replacing stainless steel and cobalt-chromium alloy implant which are used in skull, shoulder joint, spine, and dental implant. In dental field, titanium has been used as dental implant, so it becomes necessary to examine and estimate the anti-corrosion ability of Ti and its alloys at the severe conditions such as crevice corrosion and galvanic corrosion. The purposes of this study was to examine the corrosion mechanisms of the pure Ti showing good corrosion resistance under an oral corrosion environment when it is coupled with dental casting Type Ⅱ and Type Ⅳ gold alloys. These coupling corrosion mechanisms were studied in three conditions. First was by measuring the resting potential of pure Ti, when it was uncoupled and coupled with Type Ⅱ and Type Ⅳ alloys. Second was by measuring anode polarization behavior of pure Ti, Type Ⅱ and Type Ⅳ alloys, and third was by detecting dissolved ions from the pure Ti, uncoupled and coupled with Type Ⅱ and Type Ⅳ gold alloys which were immersed in 0.9% NaCl solution for 7 days. The resting potential showed a low potential value at the initial stage but increasing into a high value (to 0.18 V) with time elapse and reached a stable value. On the contrary, the potentials of Type Ⅱ and Type Ⅳ gold alloys were in their values at the initial stage of immersion, then decreased with the time and reached stable values, being higher than the value of pure Ti. When pure Ti coupled with Type Ⅱ and Type Ⅳ gold alloys, the resting potential of coupled one was between the values of each one. When Type Ⅱ and Type Ⅳ gold alloys were coupled with pure Ti, there was an increase in Ag, Cu, and Zn. Also, Zn ions released the high potential precious metal alloys, compared to the uncoupled case. Ti ion was not detected at any cases of pure Ti or coupled with gold alloys. It was thought that one of the causes of the increase in Ag, Zn, and Cu ions when Ti was coupled with dental gold alloys was that Ag, Zn, and Cu ions were selectively dissoluted from the Ag rich regions around grain boundary and the casting defects. In conclusions, the results of this study suggest that the pure Ti was very stable when coupled with the gold alloys in oral cavity.