Ce 조성 변화에 따른 Al계 비정질 형성에 관한 연구

신봉문 大田産業大學校 1993 한밭대학교 논문집 Vol.10 No.2

ABSTRACTThe studies of amorphous alloys are under active progress at the present.The reason that the study on these has started to progress briskly is that it is found that amorphous alloys, compared with crystalline alloys with the same composition, have not onlyexcellent mechanical properties but also excellent chemical properties like corrosion resistance.Though the studies on amorphous alloys up to now have been limited bo electronic and magnetic materials, this study focused on teh possibility of use as structural material rather than these materials.First, in order to obtain amorphous alloys, under condition that the uncleation and growth of crystal phase are repressed at the supercooled region between melting temperature (TM) and glass transition temperature (0.5Tm≤Tg≤0.65Tm), heated alloys up to above melting temperature must be supercooled to glass transition temperature.Considering the importance of controls of paramenters like composition, wheel speed, etc., this study fixed the revolution velocity of single roll prepared from Cu to velocity of 5500 rpm and prepared the compositions of Al-Ce(2, 3, 5, 8, 12, Ce at%).Also, in this study, the analysis of fabricated ribbon included X-ray, TEM, TG-DTA.X-ray peak variation according to composition indicated broad region of typical amorphous pattern as Ce amount increases and analysis of fabricated ribbon by TEM resulted in halo ring pattern as typical amorphous pattern.Also, TG-DTA result of ribbons according to each composition indicated exothermic peaks of first, second, thired and the first exothermic peack temperatures according to composition ranged from 180℃ to 290℃. The studies of amorphous alloys are under active progress at the present. The reason that the study on these has started to progress briskly is that it is found that amorphous alloys, compared with crystalline alloys with the same composition, have not only excellent mechanical properties but also excellent chemical properties like corrosion resistance. Though the studies on amorphous alloys up to now have been limited to electronic and magnetic materials, this study focused on teh possibility of use as structural material rather than these materials. First, in order to obtain amorphous alloys, under condition that the nucleation and growth of crystal phase are repressed at the supercooled region between melting temperature (Tm) and glass transition temperature (0.STm≤Tg≤0.65Tm), heated alloys up to above melting temperature must be supercooled to glass transition temperature. Considering the importance of controls of parameters like composition, wheel speed, etc., this study fixed the revolution velocity of single roll prepared from Cu to velocity of 5500 rpm and prepared the compositions of Al-Ce (2, 3, 5, 8, 12, Ce at%). Also, in this study, the analysis of fabricated ribbon included X-ray, TEM, TG-DTA. X-ray peak variation according to composition indicated broad region of typical amorphous pattern as Ce amount increases and analysis of fabricated ribbon by TEM resulted in halo ring pattern as typical amorphous pattern. Also, TG-DTA result of ribbons according to each composition indicated exothermic peaks of first, second, thired and the first exothermic peack temperatures according to composition ranged from 180℃ to 290℃.

錫製鍊 「스래그」로부터 「탄타륨」의 濃縮에 關한 硏究

辛奉文 大田工業專門大學 1981 論文集 Vol.29 No.-

자전 고온 반응 합성법에 의한 TiAI 금속간 화합물 제조에 관한 연구

문종태,신봉문 大田産業大學校 1995 한밭대학교 논문집 Vol.12 No.1

TiAl intermetallic compound has been extensively studied for possible high temperature structural applications because of its high specific strength at high temperature, high creep resistance, and good oxidation resistance at elevated temperatures. In addition to its good properties, an economic manufacturing routes should be developed for this material to be used more extensively. One of the promising route in manufacturing TiAl intermetallics is the Self-propagating High-temperature Synthesis (SHS) method. Uniaxial compressive pressure was applied to reacting Ti-Al compact in order to obtain fully dense TiAl. The pressure was varied as 10, 50 and 70MPa and its effect on tile densification was investigated. The reaction product was kept at 1000℃, 1200℃, and 1350℃ for variable period in order to improve homogenization and control the microstructure. With 50MPa pressure, 98% of the theoretical density was obtained.

濕式燐酸中의 金屬 ion의 分離 : 重金屬 回收의 燐酸精製

辛奉文 大田工業專門大學 1979 論文集 Vol.25 No.-

Florida 産 燐鑛石을 黃酸 分解하여 얻어지는 濕式燐酸 中의 金屬 ion을 分離해 내는方法의 하나로 溶媒抽出法을 試圖해 보았다. 本 實驗의 目的은 濕式燐酸 中에 含有된 우라늄등 主要한 金屬을 分離해 내는 것 외에도 金屬表面 處理 등에 多量 使用하는 工業用 燐酸을 濕式燐酸의 精製에 의하여 얻을 수 있는가의 가능성을 模索하는데 있었다. 實驗 結果 우라늄의 分離 및 精製 燐酸의 製造가 적당한 溶媒를 使用함으로써 가능 하였음이 判明되었고 經濟的인 工程 開發을 通해서 産業化가 이루어 질 수 있음을 알았다. 또한 濕式燐酸 뿐만 아니라 Au, U 등 重金屬을 含有한 海水와 重金屬으로 汚染펄 폐수에도 重金屬 分離를 위하여 溶媒抽出法이 效果的인 方法이 될수 있을 것으로 推測된다.

製鐵所 에너지에 對한 理論的 解析에 關한 硏究

辛奉文 大田工業專門大學 1982 論文集 Vol.31 No.-

텅스텐의 溶媒抽出에 關한 硏究

辛奉文 大田工業專門大學 1983 論文集 Vol.33 No.-

Melt Spinning법을 이용한 AI-Ce-Ni 비정질 합금 제조에 관한 연구

문종태,신봉문 大田産業大學校 1995 한밭대학교 논문집 Vol.12 No.1

Since amorphous alloys have been known to have better mechanical and chemical properties than crystalline alloys of the same composition, a great number of studies on the formation of Al-based amorphous alloys has been carried out actively. However, little has been obtained about the effect of Rare-Earth metal and Transion Metal addition on amorphous phase formed by melt spinning method. The aim of this study is to determine the compositional range of amorphous phase formation, micro structure, and thermal stability of melt-spun Al-based amorphous alloys when Ce and Ni alloying elements were added. Al-Ce binary alloys with 2,3,5 and 8at%Ce contents and Al-Ce-Ni ternary alloys with 5, 10at%Ni were chosen in this study. As Ce of Ni contents increased, the width of the X-ray peak of the rapid solidified ribbons increased indicating the formation of amorphous phases, A simmilar tendency of the compositional dependence were observed in TEM halo patten analysis. Results of DSC to measure the crystallization temperature showed two or three exothermic peaks indicating two or three crystallization steps. The temperature range of the first exothermic peaks was from between 160℃ and 360℃ for Al-Ce-Ni tenary system.

황산니켈의 회분식 결정성장

辛奉文 大田工業大學 1988 한밭대학교 논문집 Vol.5 No.2

This work concerns the crystal growth of nickel sulfate in a batch operation, which is being used for nickel plating. The specific gravity of aqueous nickel-sulfate solution varing with concentration and temperature, the solubility in water, and the rate of the crystal growth were measured, plotted and correlated. The degree of nickel-sulfate purification by recrystallization was also checked. The experiment wais carried out at nickel-sulfate concentrations in water ranging 0 to 200 gr Ni/ℓ, and at temperatures ranging 20 to 60℃. The results of this experiment can be applied to the optimization of design and operation of a batch-type nickel-sulfate crystallization precess.

急冷凝固된 Al-Cu合金의 組織에 관한 硏究

辛奉文 大田開放大學 1986 論文集 Vol.5 No.-

RCP法에 의해 제조한 Ni첨가 Cu-Zn-Al 形狀記憶 合金의 特性

辛奉文 한밭대학교 산업과학기술연구소 1993 논문집 Vol.1 No.-

The properties of Cu-Zn-Al-(Ni) shape memory alloy produced by the rapid cooling plate process has been studied. The added Ni is apt to be solubilized in the copper metrix and it forms no fine complex, so that the grain size does not reduce appreciably. The size of the refined grain on rapid cooling plate decreases remarkably down to 54㎛. The fracture stress and the strain of the refined alloy were increased by 2 and 1.5 times respectively than those of the alloy unrefined, but the shape memory effect became less a bit.