非晶質 Fe Si P 合金의 結晶化過程

孫紅在,申鉉澈,金澤基 忠南大學校 産業技術硏究所 1986 산업기술연구논문집 Vol.1 No.2

The thermal stability and crystallization process of amorphous Fe Si P alloys were studied by D.S.C and x-ray diffractometer. The results are as follows; 1) The amorphous forming range of Fe Si P alloys is O x 8. 2) Phase transformation by the crystallization occurs as follows ⅰ) x=2,4 ; amorphous → α-Fe(b.c.c) + Fe₃P(b.c.t) ⅱ) x=6,8 ; amorphous → amorphous + FeP → Fep + Fe₂P(h.c.p) → Fe₃P(b.c.t) + α-Fe(b.c.c). 3) The crystallization temperature and activation energy for crystallization are increased with increasing Si contents and presented max 718K, 110Kcal/mole at x=4, respectively and then decreased with increasing Si contents.

방사선 동시계수기의 제작

김택기 공주교육대학교 초등연구원 1968 公州敎大論叢 Vol.5 No.-

The radiation counter is one of the important instruments for the understanding of much natural phenomena. Many physicists have aleady made many kinds of radiation counters. In recnt days, many physicsts have intented to improve Geiger-Muller^ counter (1928): especially its apparatus and counting method. W. Borthe improved the G-M counter, and made the first simultaneous counter of radiation. B. Rossi and [L.M.Mott-Smith improved Borthe’s model. This writer has made the simultaneous counter of radiation to improve Rossi’ s circuit. The structure of this simultanteous counter of radiation is divided into the 4 major part: 1) G-M tube (fig-1) 2) Discriminator and amplifier(circuit-l) 3) Scaler (scale-of-26: circuit-2) 4) High voltage source of electricity and 300V. constant source of electricity (circuit-3 and circuit-4) The characteristices of the apparatus can be described as follow: 1) The pulse sent from the G-M tube to scaler can make the complete rectangular wave. 2) It can get to the fixed and unchangeable signal output without the signal imput being concerned. 3) We can freely regulate the pulse duration time. 4) In the case of using the single counter, the counting efficiency is reduced. In the case of using this simultaneons counter of radiation, however, we can conveniently get the true value without any error by the geometrical efficiency, the absorption of radiation, the infule- nces of dispersion, and sensitivity of detector. 5) It uses the scale-of-26 method which is less convenient than the decimal method, becaouse the circuit of scaler is simple. 6) This simultaneous counter of radiation contributes confidence/safety, stability and handy handling to its practical use.

Fe-Si合金의 窒化機構및 機械的 性質에 關한 硏究

金澤基,남궁석 충남대학교 공업기술개발연구소 1975 工業技術開發硏究所論文集 Vol.2 No.1

It was investigated that Fe-Si alloy specimens were manufactured by the liquid nitriding Fe-Si alloy steel plates under the conditions of comparatively short time and constant temperature 600℃. The hardness of the specimens manufactured under the varying reacted time and the constant temperature 600℃ and various times were measured by Vicker's microhardness tester. The structure was observed with the metallurgical microscope. The following results were obtained. 1) The hardness increased depending on the nitriding time untill it's value became about Hv400, Saturated value. 2) The etching layer was suddenly increased, when the heating time was more than 20hr.

폴리올레핀 첨가에 따른 PA66 소재 마찰마모특성 평가

김택기 한국고분자학회 2011 한국고분자학회 학술대회 연구논문 초록집 Vol.2011 No.2

비정질 ( Fe1-x Cox )77Si10B13 의 자기적 특성

김택기,노봉환 대한금속재료학회 1983 대한금속재료학회 학술대회 개요집 Vol.1983 No.0

자장열처리가 비정질 Fe80-xCoxSi6B14 합금의 자기적 성질에 미치는 영향

김택기,조용수,김기환 대한금속재료학회(대한금속학회) 1991 대한금속·재료학회지 Vol.29 No.6

Amorphous Fe_(80-x)Co_xSi_6B_(14)(10≤X≤70) alloys were annealed below their Curie temperatures in AC magnetic field in order to improve soft magnetic properties. Magnetization measurements were made as a function of applied AC magnetic field and annealing temperature and time. Magnetic measurement results clearly demonstrated that some beneficial effects can be provided by applying AC field during annealing, in improvement of the soft magnetic properties : a significant decrease both in coercive and in AC Power loss, and a tendency toward a square shape of hysteresis loop were observed in the our present study. The optimum experimental condition to obtain best magnetic properties for the amorphous Fe_(80-x)Co_xSi_6B_(14) alloys was determined to be AC field annealing treatment at 380℃ for 30 min with H_a≥30 Oe.

Fe-25 Cr-14 Co-2 Si-1.5 Ti 합금의 자기적 경화과정

김택기,김윤배,서원근 대한금속재료학회(대한금속학회) 1988 대한금속·재료학회지 Vol.26 No.6

The magnetic hardening process according to the heat treatment of a Fe-Cr-Co hard magnetic alloy was investigated. It could be described that the magnetic hardening process of this alloy was divided into three parts. In the heat treatment of the first stage, the thermomagnetic treatment, FeCo-rich (α₁) phases were precipitated. The aspect ratio of precipitates was determined in this stage. The heat treatment of the second stage caused precipitates to grow, improving the magnetic properties of the alloy. The alloy became brittle due to the rapid increase of the hardness by the second stage. In the heat treatment of the third stage, the concentration of the matrix (α₂) and the precipitates (α₁) changed gradually with little change in the shape and volume fraction of the precipitates. The coercive fores of the alloy increased largely in this last stage.

Alnico 5 의 열처리에 따른 2 상분리조직과 자기특성

김택기,김윤배,송세안,임동묵 대한금속재료학회(대한금속학회) 1986 대한금속·재료학회지 Vol.24 No.5

In order to study a relation between microstructures and magnetic properties in Alnico 5, Fe-24Co-14Ni-8Al-3Cu alloy was prepared by induction melting, and then optimum heat treatment procedures and microstructures of this alloy were investigated systematically. In Alnico 5, the cooling rate(c) in a magnetic field from 900℃ to 600℃ and the optimum aging time(t) at 600℃ have a relation of log(t)=0.417 log(c) + 0.884. However, the final magnetic properties are highly dependent on the cooling rate. Spinodally decomposed structures of this alloy show that the faster the cooling rate, the smaller the size of the FeCo-rich precipitates and the larger the aspect ratio. Length of the long axis of the FeCo-rich precipitates at a given cooling rate is not uniform due to the interconnection of sub sequent precipitates by magnetic field effect, and this tendency seems to be stronger when the cooling rate is slower. But the length of the short axis of the precipitates is almost same at a given cooling rate. The length of the short axis (ℓ) and cooling rate (c) in magnetic field have a relation of log (ℓ)=2.385-0.317 log(c) Optimum solution treatment temperature of the low temperature solution treatment method is 860℃. It is concluded that the low temperature solution treatment method is more desirable than the high temperature solution treatment method in improving the hard magnetic properties

저진공증착 Fe막의 자성

김택기 공주교육대학교 초등연구원 1970 公州敎大論叢 Vol.7 No.2

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강자성 Mn-Sb 박막의 자기 광학적 효과

김택기 공주교육대학교 초등연구원 1973 公州敎大論叢 Vol.10 No.-

The polycrystalline MnSb films of 800 A thickness Were deposited on glass substrates kept at room temperature under 1 X 10-5 Torr.. The magnetic and magneto-optic properties of these films in terms of atomic ratio were investigated. The saturation magnetization, Ms, and coercive force, He, of these films were measured with self-made hysteresis loop tracer. The Kerr rotation angles, ellipticities and absorption coeficients in terms of specific wave length (from 4,000 A to 7,200 A) and atomic ratio were obtained with ellipsometric method. In the Mn-Sb films the maximum value of Ms, 700 gauss, and mimimum value of He, 180 Oe, were obtained in the case 50% Sb in Mn. In this case the Kerr rotation angle was 1.3x 10~2 rad. at λ=4,200 A, the minimum value of ellipticity was 1.4X10-2 rad. λ = 4,800 A. Therefore the Mn-Sb compound thin films which atomic ratio is 1 : 1 are most adequate of the memory element in computer.