예민화 (銳敏化) 열처리된 오스테나이트계 스테인리스강의 입계부식 거동

윤병하,김태호 대한금속재료학회(대한금속학회) 1989 대한금속·재료학회지 Vol.27 No.7

This study examined the degree and the avoidable conditions of the intergranular sensitization on the commercial stainless steel(STS 304, 304L, 316, 316L) in the temperature range of 450℃ to 850℃. The electrochemical potentiokinetic reactivation test was used in detecting the degree of sensitization of STS 304, 304, 316 and 316L in an electrolyte which contained sulfuric acid with KSCN as an additive. On the isothermal sensitization process, the chief variables choosed the sensitizing temperatures (580, 650, 750, 800℃) and time of the isothermal hold (0.5, 1.0, 10, 24, 72 hr). In the case of isothermal heat treatment, the degree of sensitization was increased with the heat treating time as 580℃ and 650℃. but the degree of sensitization was derreased by long heat treating time at 730℃ and 800℃, because of a self-healing of the chromiume depleted zone. The degree of sensitization was reduced as the carbon content in the austenitic stainless steel decreased. The molybdenum in the austenitic stainless s eel increased the intergranular corrosion resistance. As continuously cooled from 1050℃ to 450℃, STS 304, 304L, and 316 were not sensitized at cooling rates faster than 5, 0.4, and 0.25℃/sec, respectively. as continuously cooled from different annealing temperature under constant cooling rate, the degree of sensitization was extremely served at 900℃ but decreased above 950℃.

Pickling廢液으로부터 磁性 Ferrite의 原料가 되는 酸化鐵의 製造

尹秉河,鄭潾相,金圭鎬 경북대학교 공과대학 1978 工大硏究誌 Vol.7 No.-

The production of a-Fe2O_3 from the waste picklic solution has been investigated. Anhydrous iron chloride can be obtained by the dehydration of waste picklic solution in dried nitrogen gas, and a-Fe_2O_3 was produced by the oxidation of anhydrous iron chloride under the various conditions: the oxidation reaction temperature, the air flow rate, the water content, and the evaporation temperature of anhdrous iron chloride. The experimental results are summarized as following; The dehydration temperature in iron chloride obtained from waste picklic solution is 210℃. The formation of a-Fe_2O_3 from anhydrous iron chloride in using dry air is that the reaction temperature is 700℃ and air flow rate is below 3l/min. Pure a-Fe_2O_3 single phase can be obtained at 500℃ by adding water of 2.2v/o to the air. The fine and uniform particles are obtained as reaction temperature, the water content in air, and vaporization temperature decrease. However the air flow rate is not so effective on it.

킬힐, 맨발, 운동화에 따른 굽 높이가 균형능력에 미치는 영향

윤병하,이진백,노다혜,오선옥,홍승표 대한보조공학기술학회 2012 대한보조공학기술학회지 Vol.4 No.-

목적 : Tetrax(Tetrax Portable Multiple System)를 이용하여 맨발, 운동화, 킬힐의 착용에 따라 균형능력에 차이가 있는지를 알아보고자 한다. 연구방법 : 본 연구는 2010년 8월 31일~9월 7일 D대학에 재학 중이고, 연구참여에 동의한 여학생 20명을 대상으로 평가를 실시하였다. 균형평가는 Tetrax를 통해 시각과 체성 감각의 유무, 머리의 좌우와 앞뒤의 변화를 요구하는 8개의 자세에서 검사를 시행하였고, 맨발, 운동화, 킬힐은 무작위 선정하여 시행하였다. 결과 : 킬힐을 착용했을 때 안정성 지수(Stability index)가 맨발 또는 운동화 착용보다 높았고, 체중 분포 지수(Weight distribution index)는 정상치 범위보다 낮았으며, 낙상 지수(Fall index)는 위험범위에 속하였다. 결론 : 킬힐을 착용했을 때 맨발이나 운동화보다 자세불안정으로 인하여 낙상 위험이 높은 것으로 나타났다. Purpose : To find the effect of changes related to bare foot, sneaker, and kill heel on the posture balance Method of. Research : This study took survey over 20 female students enrolled in D University from Aug. 31st to Sep. 7th of 2010 and also evaluation with willing participants. Evaluation was done with eight different postures that require presence of visual and somatesthesia, left & right/forward & backward changes of the head. Each evaluation took 32 seconds. In the same manner, barefoot, sneaker, and kill heel were randomly selected and conducted. Result : Balance ability measurement via Tetrax showed higher stability index with bare foot or sneaker than kill heel. Weight distribution index was lower than the normal range with kill heel and Fall index was in range of danger. Conclusion : When kill heel was worn, danger of fall injury was prominent due to posture imbalance.

酸化第一銅의 matte形成에 對한 反應速度定數 및 活性化 energy에 關한 硏究

尹秉河 경북대학교 공과대학 1975 工大硏究誌 Vol.4 No.-

Matte formation which occurs in the chemical reaction between Cu_2O and FeS Studied with the equilibrium constant calculated thermodynamically. The purpose of this investigation was to determine directly the reaction-rate constant at 1, 200˚, 1,300˚ and 1,350˚, and to calculate activation energy of the reaction utilizing Arrhenius equation. The resulting reaction rate constants at 1,200, 1,300 and 1,350℃ were 0.80×10 exp (-3), 1,014×10 exp (-3) and 1,069×10 exp (-3) mol/cm^2-min, respectively and the activation energy was 3.349Kcal/mol. The exchange reaction of Cu_2O to Cu_2S by FeS found to be prominent only at the temperature of 1,300℃ or above.

過共晶鑄鐵의 初晶세멘타이트의 成長形態 및 組織에 대하여

尹秉河,洪俊杓 慶北大學校 1976 論文集 Vol.21 No.-

Directional solidification experiments were conducted on Fe-C hypereutectic alloys to investigate the growth pattern of the primary cementite and the relation between the eutectic structures and the primary cementite. The effect of manganese and the growth rate on the shape of the primary cementite were studied. The shape of the primary cementite has been generally considered to be a plate-like type. However, in the current investigation, it was observed that the primary cementite has a characteristic shape like a letter "L" in Fe-C-Mn alloy system. A higher content of manganese and a slower growth rate permit the formation of this type of a primary cementite. At the faster growth rate, a plate-like type becomes favorable.

溶融 Al중에서의 水素의 擴散

尹秉河,金東義,李基大 慶北大學校 産業開發硏究所 1977 硏究報告 Vol.5 No.-

The diffusivity of hydrogen in liquid aluminum was determined by an unsteady stategas-liquid metal diffusion cell technique. The diffusion cell was formed by immersing an alumina absorption tube containing hydrogen gas at 1 atm in a bath of stagnant liquid aluminum. The main results are summarized as follows. It is confirmed that the unsteady state gas-liquid metal diffusion cell technique is suitable for studying the diffusion of gases in liquid metals. The rate of absorption of hydrogen in stagnant liquid aluminum appear to be controlled by the diffusion of hydrogen in the melt and can be described by the appropriate diffusion equation. The diffusion coefficients, D_H, for hydrogen in liquid aluminum can be described as follow in the temperature range of 726℃∼817℃ D_H=2.66×10exp(-1) exp(-(3887±491)/(RT))㎠/sec

熔融 Cd 中 Zn 과 Cu, Ag, In, Bi, Pb 및 Sn의 相互作用係數

尹秉河,金大龍 慶北大學校 1982 論文集 Vol.34 No.-

Zinc activities in dilute Cd-Zn and Cd-Zn-X(where, X; Cu, Ag, In, Bi, Pb and Sn)molten alloys have been measured in the temperature range of 450 to 570℃, using an e.m.f. measuring technique. The concentration cell utilized was pure Zn(1)|[ZnCl_2 (in fused KCl+LiCl eutectic electrolyte)]|[Cd-Zn or Cd-Zn-X(1)] The activities of zinc deviated positively from the Raoult's law. The activity coefficients of zinc in the ternary systems were decreased with increasing Cu and Ag, but increased with increasing In, Bi, Pb and Sn. The interaction parameters of the zinc-zinc and zinc-third element were found to be a linear functions of the reciprocal absolute temperature and were expressed by the following relations. ε^Zn_Zn = -930.7/T-6.4074 ε^Cu_Zn = -4070/T-4.3644 ε^Ag_Zn = -7261/T-5.1039 ε^In_Zn = -9769/T+3.5979 ε^Bi_Zn = 1585.6/T+3.1725 ε^Pb_Zn = -8410/T+2.0508 ε^Sn_Zn = 984/T-0.1943

熔融 Zn-Cd, Zn-Bi, Cd-Bi系 및 Zn-Cd-Bi系에서 각 成分金屬의 活動度 측정

尹秉河,金大龍,金炳宰 慶北大學校 1984 論文集 Vol.38 No.-

Activities of the component metal in Zn-Cd, Zn-Bi-Cd alloys have been determined at 823 K by touch instant electromotive force method. The cell employed was ◁표삽입▷ (원문을 참조하세요) Activities of each component metal which obtained by T.I.E. method showed similar tendencies with the compare of the equilibrium concentration cell method. But activities of the noble metals showed small difference in some range. This difference was made from the substitution reactions in the molten electrolyte, and from calculation's error.

多段式 回分 抽出에 依한 토륨의 精製

尹秉河,崔舜惇 慶北大學校 産業開發硏究所 1976 硏究報告 Vol.4 No.-

Refining of crude thorium nitrate solution were carried out with 50% TBP―Xylene by a 3 stage countercurrent multisage extraction. The best results were obtained as follow. A refined thorium oxide of 99.6% purity was obtained (in higher recovery) as nearly pure rare earths when the crude thorium of 83.2% purity in 8N nitric acid was treated by 3 stage counterrent extraction with 50% TBP-Xylene. In order to obtain the thorium of high purity and high yield, the follwing processes were necessary. (1) Increase in number of extraction steps (2) addition of scrubbing stage, and (3) Applicating freshing solvent, instead of feed solution, to the lost extract.

溶融 Pb중의 Zn과 微量溶質 Bi, Su 및 Ag간의 相互作用係數

尹秉河 慶北大學校 1980 論文集 Vol.30 No.-

The reversible concentration cells of the type: Zn(l)/ZnCl_2 in (KCI+LiCl) eut(l)/Pb-Zn or Pb-Zn-X(l) have been employed for a study of the interaction parameters of dilute Pb-Zn and Pb-Zn-X alloys in the range of 0.01〈N_zn or (N_χ)〈0.07 over the temperature interval of 460 to 640°. Measurements have been made of the influence of bismuth, tin, cadmium, and silver on the activity coefficient of zine in liquid lead. The results have been summarized in terms of first order interaction parameters which can be expressed as a function of temperature by the relation. ε^Zn_Zn=13,860/T-9.22 ε^Cd_Zn=3.750/T-4.01 ε^Bi_Zn=-3,113/T+3.01 ε^Ag_Zn=-5,113/T+3.92 ε^Sn_Zn=4,970/T/4.88