산소와 구리의 공정반응에 의한 구리와 알루미나의 직접접합

이임렬,유환성 단국대학교 신소재기술연구소 1991 신소재 Vol.1 No.-

본 연구에서는 구리표면의 구리-산소간의 공정반응에 의하여 형성된 Cu-Cu_2O 공용액상 피막으로 고체 Cu금속과 Al_2O_3세라믹을 압력없이 직접접합시키는 방법을 조사하였으며 접합조건에 따른 접합특성, 파면 및 계면분석을 SEM, EDS, XRD 및 peeling 시험을 통하여 분석하였다. 1.5×10^-1 torr 진공하에서 1015℃의 온도에서 산화시킨 구리시편은 미세한 산화물 Cu_2O가 표면에 잘 형성되었다. 그후 공정온도 1065℃ 이상의 접합온도 1075℃에서 5분간 10^-3 torr의 진공하에서 직접접합시킨 시편은 접합력이 우수한 Cu/Al_2O_3 접합이 되었으며 접합후 구리기니 내에는 Cu2O가 석출된 공융조직을 갖고 있었다. 3분 산화조건에서 충분한 액상이 형성되어 29kg의 최대 접합강도를 보였으며 산회시간이 이보다 짧거나 불충분한 액상의 형성이나 산화물내의 균열 등으로 결합력이 저하하였다. 파단후 Al_2O_3 표면에는 Cu_2O nodule이 존재하였고 Cu족에는 nodule이 빠진홈을 관찰할 수 있었는바 cu2O/Al_2O_3계면 접착력은 Cu.Cu_2O계면보다 강함을 알 수 있었다. 또한 파단면에는 반응 생성물 CuAlO_2가 접합중 형성되었으나 이 반응층 두께는 SEM분해능 이하인 매우 얇은 것으로 생각된다. The direct bonding between Cu and Al_2O_3, utilizing Cu-Cu_2O skin melt formed on Cu surface by eutectic reation of Cu-O, is investigated in this study. The bond strength, fracture surface and interface structure with bonding conditions have been studied using SEM, EDS, XRD and peeling test. A fine Cu_2O is formed on the surface of Cu with oxidation at 1015℃ under 1.5×10^-1torr vacuum. After oxidation, the bonded specimen conducted at 1075℃ in 10^-3torr vacuum for 5minutes, higher temperature than its eutectic temperature of 1065℃, has a good strength having a Cu_2O precipitated structure in Cu matrix upon cooling. It has been found that the maximum bonding force of 29kg is obtatined for 3 minutes of oxidation. However, the adhesion forces are decreased with shorter or longer oxidation than this due to the formation of insufficient liquid skin or crack within oxide. After peeling test, Al_2O_3 surface is covered with Cu_2O nodules which are pulled out of Cu surface indication that Cu_2O/Al_2O_3 adhesion force is stronger than that of Cu/Cu_2O. Moreover a reaction phase of CuAlO_2, thought to be very thin layer below the resolution of SEM, is also formed during the bonding process.

冷間加工의 磨耗에 對한 影響

李任烈 단국대학교 1986 論文集 Vol.20 No.-

The wear experiment was conducted on couples consisting of iron, nickel, Fe-36% Ni and 3% silicon steel pins sliding against a tool steel disc. It has been found that the wear rate in air at room temperature lis independent to me hardness. The experimental observations are well related to the oxidation characteristics. However, the rate of oxidative wear is much higher than that for static oxidation due to the difference in the activation energy for oxidative wear. The lower energy for oxidational wear indicates that the rubbing surfaces are mechanically activated and high diffusivity path for diffusion of matrix elements and oxygen are produced during the sliding motion. The higher wear rate for cold-worked samples than for the annealed ones are associated with the higher oxidation rate for the cold-worked specimen.

산소와 구리의 공정반응에 의한 구리와 알루미나의 직접접합

이임렬(Rhim Youl Lee),유환성(Hwan Song Yu) 단국대학교 신소재기술연구소 1991 신소재 연구논집 Vol.1 No.-

역삼투와 투과 증발막 공정의 비교 2: 실험적 해석

Rhim Ji Won,Bae Seong Youl,Kimura Shoji,Robert Y.M. Huang 한국막학회 1993 멤브레인 Vol.3 No.1

역삼투 및 투과 증발막 분리공정이 nylon 4 blended 막을 사용하여 물-에탄올 계에 대하여 실험적으로 비교되어졌다. 위 두 공저의 이론적 비교를 다루었던 전 논문과 마찬가지로 투과 증발 공정의 분리 효율이 역삼투 공저의 경우 보다 더 좋음을 알 수 있었다. 그러나 투과도 데이타는 막의 결함들로 인하여 엉뚱한 결과를 보였다. Reverse osmosis(RO) and pervaporation(PV) membrane separation proceaes were compared with each other experimentally for the system of water-ethanol mixtures by using nylon 4 blended membranes. The separation effciencies of PV were better than those of RO as expected in previous paper covering the theoretical comparisons of both processes, however tbe permeabilities data showed erraerie results due to the membrane imperfections.

활성슬러지 공정에 관한 Kinetic Model의 비교

林鎭男,姜相勳,裵星烈 漢陽大學校 環境科學硏究所 1985 環境科學論文集 Vol.6 No.-

CMAS공정을 설명하는 데 사용되어 온 Kinetic Model들을 비교하고 가장 좋은 Model을 선택하기 위하여 연구하였다. 혼합미생물 배양의 정상상태 거동을 관찰하기 위하여 세포물질의 순환이 없는 등온, 연속흐름의 완전혼합 Aeration Tank를 사용하였다. Glucose를 증식제한기질로 사용하여 11개의 dilution rate에서 실험하였다. 실험을 통하여 얻어진 여러 data들은 최소자승법과 iterative minimum search technique에 의해 여러 Model의 Parameter를 추정하는 데 사용되었다. 미생물 사멸계수를 포함한 Monod, Two-phase, Teissier, Contois, Moser, Grau 등 6개의 Model을 비교하였다. Teissier에 의해 제안되었던 Model이 다른 Model보다 좋은 것이었으며, Two-phase Model이 가장 부적합하였다. 낮은 dilution rate(??)에서는 COD의 90% 이상이 제거되었다. It was studied to compare kinetic models which have been used to elucidate CM-AS process and to select the best model. To investigate the steady-state behavior of heterogeneous microbial populations, completely mixed aeration tank under isothermal and continuous flow condition without cell recycle was used. A series of experiments were carried out at eleven dilution rates using glucose as the growth limiting substrate. Multiresponse data obtained through experiments in an aeration tank were made use of estimating the parameter values in various models by using the least squares criteria and an iterative minimum search technique. The six models of Monod, Two-phase, Teissier, Contois, Moser and Grau, with microbial decay coefficients were compared in this study. The selection of the best model among those investigated was carried out by employing the F-test and an analysis of the sum of squares of residuals. As the result, the model proposed by Teissier was significantly better than the other models which were tested, and Two-phase model was not fitted to express CMAS process. At low dilution rates(??), it was removed over 90% of COD.

역삼투와 투과 증발막 공정의 비교 1: 이론적 해석

Rhim Ji Won,Lee Kew Ho,Bae Seong Youl,Robert Y.M. Huang 한국막학회 1993 멤브레인 Vol.3 No.1

본 논문에서는 역삼투막 공정과 투과 증발막 공정이 Paul과 Ebra-Lima 모델을 사용하여 이론적으로 서로 비교되어졌다. 이 모델로부터 막내에 있는 액의 농도를 역삼투 공정의 경우 압력이 막의 윗쪽에 가하여졌을 때 (반면에 투과 증발 공정의 경우는 가하여진 압력이 무한대일 때) 막 -n-hexane 그리고 rubber 막-benzene 계들에 대하여 계산되어졌다. 또한 polyethylene-n-hexane 그리고 polyethlene-benzene 계들에 대하여 역삼투 및 투과 증발 공정의 투과도가 계산되어졌고 비교되어졌다. 이론적으로는, 투과 증발 공저으이 투과도가 역삼투 공저의 투과도 보다 더 컸음을 알 수 있었다. Reverse osmosis(RO) and pervaporation(PV) membrane processes were compared with each other theoretically by using Paul and Ebra-Lima model. From this model the concentrations of liquid within the membrane when pressure was applied to the upper compartment(for PV case, the applied pressure is infinite) were calculated for rubber membrane-n-hexane and rubber membrane-benzene systems. The permeabilities of RO and PV were also calculated and compared for polyethylene film-n- hexane and polyethylene film- benzene systems Theoretically, the permeabilities of PV membrane were greater than those of RO membrane.

Zr-Ni 합금욕에서 액상침적법에 의한 Monel 400 에 복합재료 보호층의 형성

이임열,조선욱,박상현 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.1

83Zr-17Ni alloy coatings on Monel 400 substrate were produced by the hot dipping. The coating layer of 30 ㎛ thickness was obtained at 1050℃ for 1 min. dipping. The formation of Zr₂Cu was found at the substrate/coating interface during the hot dipping. The selective oxidation during the heat treatment led to the formation of Zr-rich oxide on the coating layer containing Zr. It was found that the coating layer was consisted of an outer ZrO₂ layer and an inner oxide/metal composite layer with a conversion heat treatment at 1030℃ for 20hr. These oxide and composite layers resulted in an increase on the hardness. The oxidation rate was decreased with hot dipping and also with conversion. It was proved that the resistance to spallation was enhanced by coating.

이온 주입에 의한 강의 질화

이임열 대한금속재료학회(대한금속학회) 1987 대한금속·재료학회지 Vol.25 No.6

Accelerated N^+ ions were implanted into iron and steel to study the change of the mechanical properties which are sensitive to the surface. The hardness of tool steel (SKD 61) was increased by about 50% with implantation at dose of 5×10^(16) N^+ ions/㎝² at 50 keV beam energy. It was found that both the hardness and the fatigue life ware increased with increasing dose of N^+ ions. A dry wear test conducted on pin-on-disc showed that the wear rate of implanted samples was greater than that of unimplanted ones due to the change in oxidation behavior with implantation, while the rate of running-in-wear was decreased by implantation under lubricated condition. Evidence from TEM supported the existence of nitride precipitates of particle size of 10-100 A˚at dislocations in implanted pure iron. SIMS analysis was employed to study the chemical composition of the implanted layer.

Ti 및 Zr 증착에 따른 알루미나와 Inconel 600 간의 Ag-Cu 합금을 사용한 활성 브레이징 접합

이임열,조선욱 대한금속재료학회(대한금속학회) 1995 대한금속·재료학회지 Vol.33 No.10

Alumina ceramics and Inconel 600 metal were bonded using conventional brazing filler metal of Ag-Cu alloy after Ti and Zr coatings onto alumina surface. Then the effect of metal coatings on the interfacial structure and metallurgical behavior at interface between the filler metal and Inconel 600 were investigated. It was found that a prior sputter coating of Ti or Zr was effecive in wetting even to the alumina surface of difficult-to-wet with Ag-Cu brazing alloy. The bonding shear strength employing Ag-Cu brazing alloy was found to be increased from zero to 12 MPa with 3 ㎛ Ti coating. Although this bonding strength was lower than that of 25 MPa for using active brazing metal of Ag-Cu-Ti, the active metal coating method prior to brazing with Ag-Cu alloy might give a benificial effect associated with a lower melting temperature of eutectic Ag-Cu alloy compared to Ag-Cu-Ti. And also it was found that the Ti coating and/or Ti segregation during brazing enhanced the separation of silver- and copper-rich liquid phaes in molten filler metal causing a coarse microstructure.

Bioprogressive Mechanism에 의한 CIⅢ부정교합의 치험예

정규림(Kyu-Rhim Chung),권기열(ki-Youl Kwon) 대한치과교정학회 1985 대한치과교정학회지 Vol.15 No.2

This present paper describes 3 clinical cases which were treated with Bioprogressive mechanism. Each patient has shown a deficient maxilla combined with prognathic and steep mandible. The purpose of treatment was planned to obtain the forward growth of maxilla and redirectioning of mandibular growth. The most noteworthy approach in the treatment was the application of Cl Ⅲ intermaxillary elastics with upper protraction utility arch immediately after rapid moxillary expansion. In the analysis of the data obtained from pre-and post treatment lateral cephalogram, the result achieved by this method is very favolable to the corrextion of anteroposterior relationship of maxilla and mandible.