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RISS 인기검색어
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- 저자 : 盧正剋 (검색결과 7 건)
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局部義齒 프레임워크用 卑貴金屬合金의 鑄造組織과 硬度에 關한 硏究
盧正剋,李基大 慶北大學校 齒科大學 1985 慶北齒大論文集 Vol.2 No.1
In recent years, base metal alloys have almost replaced gold in the fabrication partial denture frameworks due to their relatively low density and high hardness. The main problems with the base metal alloys can be associated with their excessive hardness and inadequate elongation. The purpose of this study was to investigate the relationship between the microstructure and the hardness of chromium cobalt alloys depending on the cooling methods followed by casting. The 1st group was quenched in 0℃ water, the 2nd, bench cooled at room temperature (25℃), and the 3rd, slowly cooled in the furnace from 700℃ to room temperature(25℃) The microstructures of each specimen were compared by means of photomicrograph taken by metallurgical microscope. In addition to this, the mechanical characteristics of each specimen were obtained using the Rockwell Hardness Number(RHN). The results were obtained as follows. 1) In the cooling of cobalt-chromium alloys for partial denture, the slow cooling method (i. e. bench or furnace cooling) considered more profitable than the rapid cooling method(i. e. quenching at 0℃ water). 2) The microstructure of alloy casted by direct gas flame method showed some miroporosity and casting defects. The grain particles in the slowly cooled alloy were more finer than the rapidly cooled alloy. 3) The hardness value of the slow cooling method(R. H. N. value:about 46) appeared higher than the rapid cooling method(R. H. N. value: about 36).
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齒科用 非貴金屬合金의 物理的 性質에 미치는 鑄型溫度의 影響
盧正剋,曺光憲,李基大 慶北大學校 齒科大學 1986 慶北齒大論文集 Vol.3 No.1
齒料用 非貴金屬合金으로 널리 使用되고 있는 니켈 - 크롬系 合金인 Ticonium Premium 100 과 코발트 - 크롬系 合金인 Regalloy를 對象으로 500, 600, 700, 800, 900 및 1,000℃의 鑄型溫度로 變化시켜 遠心鑄造한 後, 硬度 및 引張强度를 測定하고 微細組織과 引張試 片破斷面을 觀察하여 아래의 結果를 얻었다. 니켈 - 크롬系 合金인 Ticonium Premium 100은 鑄型溫度가 上昇할수록 結晶粒이 粗大하게 變化함에 따라 硬度 및 引張强度도 多少 減少를 나타내었다. 코발트 - 크롬系 合金인 Regalloy는 鑄型溫度가 上昇할수록 結晶粒이 粗大하게 變化함에 따라 硬度 및 引張强度의 顯著한 減少를 나타내었다. 코발트 - 크롬系인 Regalloy는 니켈 - 크롬系인 Ticonium Premium 100에 비해 硬度인 引張强度가 높게 나타났다. 引張試片 破斷面은 두 合金 모두에서 鑄型溫度가 上昇할수록 微細氣孔이 破斷面의 中心部에 集中되는 傾向이 增加하였으며 延性破斷에서 脆性破斷으로 轉移되는 樣相을 觀察할 수 있었다. 良質의 鑄造組織을 얻고 鑄造體의 適合性을 向上시키기 위해서는 適切한 材料에 따른 適切한 鑄型溫度의 選擇이 要求된다. The purpose of this study was to investigate the effect of mold temperature on the change in microstructure and physical properties of Ticonium Premium 100 (Ni-Cr alloy) and Regalloy (Co-Cr alloy). Tensile and hardness specimens were casted from the two types of alloys by centrifugal casting machine in mold temperatures of 500, 600, 700, 800, 900 and 1,000℃. After testing the hardness and the tensile strength of castings, the microstructure and the pattern of fracture were investigated and correlated with the above two mechanical properties. The results were as follows : As the grain size of Ticonium Premium 100 increased with the increase of mold temperature, the hardness and the tensile strength reduced slightly with the increase of grain size. As the grain size of Regalloy increased with the increase of mold temperature, the hardness and the tensile strength reduced remarkably with the increase of grain size. The values of hardness and tensile strength obtained from Ticonium Premium 100 were lower than those from Regalloy.
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齒科用 非貴金屬合金의 物理的 性質에 미치는 鑄型溫度의 影響
曺光憲,盧正剋,李基大 대한치과기재학회 1985 대한치과재료학회지 Vol.12 No.1
齒科用 非貴金屬合金으로 널리 使用되고 있는 니켈-크롬系 合金인 Ticonium Premium 100 과 코발트-크롬系 合金인 Regalloy 를 對象으로 500, 600, 700, 800, 900 및 1,0000℃의 鑄型溫度로 變化시켜 遠心鑄造한 後, 硬度 및 引張强度를 測定하고 微細組織과 引張試片 破齒面을 觀察하여 아래의 結果를 얻었다. 니켈-크롬系 合金인 Ticonium Premium 100 은 鑄型溫度가 上昇할수록 結晶粒 이 粗大하게 變化함에 따라 硬度 및 引張强度도 多少의 減少를 나타내었다. 코발트-크롬계 合金인 Regalloy 는 鑄型溫度가 上昇할수록 結晶粒이 粗大하게 變化함에 따라 硬度 및 引張强度의 顯著한 減少를 나타내었다. 코발트-크롬계인 Regalloy 는 니켈-크롬系 合金인 Ticonium Premium 100 비해 硬度 및 引張强度가 높게 나타났다. 引張試片 破齒面은 두 合金 모두에서 鑄型溫度가 上昇할수록 微細氣孔이 破齒面의 中心部에 集中되는 傾向이 增加하였으며 延性破斷에서 脆性破斷으로 轉移되는 樣相을 觀察할 수 있었다. 良質의 鑄造組織을 얻고 鑄造本의 適合性을 向上시키기 위해서는 適切한 材料에 따른 適切한 鑄型溫度의 選擇이 要求된다. The purpose of this study was to investigate the effect of model temperature on the change in microstructure and physical properties of Ticonium Premium 100(Ni-Cr-alloy) and Regalloy(Go-Cr alloy). Tensile and hardness specimens were casted from the two types of alloys by centrifugal casting machine in mold temperatures of 500, 600, 700, 800, 900, and 1,000℃. After testing the hardness and the tensile strength of castings, the microstructure and the pattern of fracture were investigated and correlated with the above two mechanical properties. The results were as follows: As the grain size of Ticonium Premium 100 increased with the increase of mold temperature, the hardness and the tensile strength reduced slightly with the increase of grain size. As the grain size of Regalloy increased with the increase of mold temperature, the hardness and the tensile strength reduced remarkably with the increase of grain size. The values of the hardness and the tensile strength obtained from Ticonium Premium 100 were lower than those from Regalloy. As the mold temperature increased, the fractured surfaces of tensile specimens in the two types of alloys showed the tendency to form large voids in the center of specimens. Thus the ductile fracture was changed into the brittle fracture with the increase of mold temperature. There was the needs for the users to select the proper alloys and to control the mold temperature accurately in order to obtain the good and suitable castings.
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