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산화물 (TiO2) 로부터 자전연소반응에 의한 TiC 분말제조
원창환,강복석,천병선 대한금속재료학회(대한금속학회) 1993 대한금속·재료학회지 Vol.31 No.5
The experimental results for the fabrication of TiC powder from TiO₂by self-combustion reaction are summerized as follows; 1) The mole ratio of Mg was the greatest affecting factor in the reaction and the mole ratio of C, particle size of Mg, mixing times affected the reaction as well. 2) MgO and Mg were completely removed by leaching in the 20% HCl solution. 3) The TiC powders had a spherical shape and the particle size was 0.3-0.4 microns with a narrow distribution. 4) Purity of manufactured TiC powder was about 99.925 weight percent.
수소환원법에 의한 수용액중 Ni-Al2O3 복합분말 제조
김동진,원창환,강복석,길기억 대한금속재료학회(대한금속학회) 1994 대한금속·재료학회지 Vol.32 No.7
Ni-Al₂O₃ composite powders were prepared by reduction of Ni^(++) from ammoniacal nickel sulfate solution on alumina core by hydrogen gas at elevated temperature and pressure. The reduction rate and the porperties of nickel layer were investigated by SEM, X-ray, size and chemical analysis. The reduction of Ni^(++) showed the maximum value when the molar ratio of NH₃/Ni^(++) was 2. In order to prevent the agglomeration of Ni powder and act as catalysis for reduction, Fe^(++) should be required and the anthraquinone was slightly influenced as catalysis. The concurrent addition of Fe^(++) and anthraquinone catalytically increased nickel deposition reaction. Optimum condition obtained in this study was reduction temperature 130℃, stirring speed 700rpm, hydrogen partial pressure 350psi and reduction time 45mins. Then the prepared composite powder obtained uniform and continuous nickel coating layer of nodule shape on alumina particles.
Sn- Bronze 계 마찰재료의 소결중 미세조직의 변화
김주완,송영두,강복석,강수석,강석중 대한금속재료학회(대한금속학회) 1989 대한금속·재료학회지 Vol.27 No.2
The microstrure evolution of a 78.0 Cu-7.1 Sn-12.5 Fe-2.4 Pb(wt%) alloy, metal composition of a typical Cu-Sn base friction material, has been studied during pressure (1.5 Mpa) and pressureless sintering up to 810℃ for various times. Overall microstructural changes during sintering were found to be determined by the reaction between Cu and Sn. The Sn melts upon heating spread alone the capillaries leaving pores at their sites and form ε phase. The pores collapsed during subsequent pressure sintering at higher temperatures. Upon heating ε phase appeared to transform into γ and β phases, which remelted eventually by reverse peritectic reactions. Fores, however, formed again at the sites of the intermediate phases, when the sintering pressure was relieved in the temperature range of peritectic reactions. Remelting of the intermediate phases could thus enlarge the size of pores in Cu-Sn base materials. A good homogeneous microstructure was obtained after sintering at 810℃ for about 1 hr under 1.5 Mpa.
Ni 피복된 Al2O3 입자분산강화에 의한 Al 기 복합재료 제조
최진일,원창환,강복석,양태성,서영식 대한금속재료학회(대한금속학회) 1996 대한금속·재료학회지 Vol.34 No.5
The experimental results from the fabrication of AC4C/Ni-coated Al₂O₃ composites by oxide dispersion strengthening are summerized as follows; 1) Optimum condition obtained in Ni-Al₂O₃ composites powder preparation was molar ratio of NH₃/Ni^(++) 1.5 : 1, reduction temperature 130℃, stirring speed 600rpm, hydrogen partial pressure 350 psi and reduction time 60 mins. 2) Ni coating to Al₂O₃ surface improved wettability by decreasing surface tension of the matrix and particles. 3) The tensile strength, hardness and wear resistance increased with increasing the volume fraction and decreasing the particle size. In case of the tensile strength at 12vol.% was about 25% higher than that of matrix alloy(Al-2Cu-2Mg).