• 열처리공학회지
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• 제19권3호
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• pp.149-155
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• 2006

The effects of eight types of spheroidizing annealing conditions including annealing temperature, annealing time, cooling rate, and gas atmosphere in the annealing furnace on the microstructure were determined in SM45C steel which has been widely used for automotive parts. The well-developed spheroidized structure and minimum hardness were obtained when the steel was heat-treated 6 hours at $740^{\circ}C$, cooled to $710^{\circ}C$ at a cooling rate of $24^{\circ}C/h$, and then kept for 7 hours at the $710^{\circ}C$ followed by air cooling. In order to increase the productivity and to save the manufacturing cost, it is desirable to apply a faster cooling rate in the spheroidizing annealing. It was found that air cooling was the fastest cooling rate applicable to the SM45C steel. The steel heat treated in air showed the decarburized layer of about $110{\mu}m$ in thickness at the surface of the specimen, resulting in serious problems in the quality of the quenched product.

• 열처리공학회지
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• 제19권5호
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• pp.270-279
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• 2006

The effects of eight types of spheroidizing annealing conditions including annealing temperature, annealing time, cooling rate, and furnace atmosphere on the microstructure and hardeness were determined in SCM440 steel which has been widely used for automotive parts. The well-spheroidized structure and minimum hardness were obtained when the steel was heat-treated at $770^{\circ}C$ for 6 hours, cooled to $720^{\circ}C$ at a cooling rate of $24^{\circ}C/h$, and then kept for 7 hours at the $720^{\circ}C$ followed by air cooling. In order to increase the productivity and to save the manufacturing cost, it is desirable to apply a faster cooling rate to the spheroidizing annealing. It was found that a cooling rate of $100^{\circ}C/hr$ was the fastest cooling rate applicable to the SCM440 steel among the four cooling rates used in this study. The microstructure consisted of ferrite and very fine spheroidized cementite when the steel was annealed for 13 hours at $720^{\circ}C$ below $A_{C1}$ temperature. This was caused by the short annealing time and the retarding effect of Cr and Mo on both the dissolution of pearlite to cementite and coarsening of spheroidized cementite. The steel heat treated in air showed the decarburized layer of about $125{\mu}m$ in thickness at the surface.

• Journal of information and communication convergence engineering
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• 제3권4호
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• pp.167-171
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• 2005

In this paper, the resonance characteristics of SMR-type FBAR devices annealed by three different annealing methods are investigated and compared. The resonance characteristics could be effectively improved by the proposed efficient annealing method which optimizes the annealing conditions. It seems very useful for improving the performance of the SMR-type FBAR devices as a cost-effective way.

• 전기전자학회논문지
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• 제25권3호
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• pp.467-472
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• 2021

고온에서도 반도체 소자의 안정적인 동작이 필요하다. 반도체 소자의 구조중에서 고온에서 불안정한 전기적 응답을 야기할 수 있는 영역은 금속과 반도체가 접합하는 콘택층이다. 본 연구에서는 p형 SiC 층위에 니켈-실리사이드(NiSix)의 콘택층을 형성하는 공정과정에 포함되는 어닐링 공정 조건이 콘택 저항의 비저항과 전체 저항에 미치는 효과를 고찰하였다. 이를 위해, 4인치 p형 SiC층 위에 전송길이 이론(transfer length method: TLM) 측정을 위한 알련의 전극 패턴들을 형성하였고, 어닐링 온도(1700와 1800℃)와 어닐링 시간(30와 60분)을 달리하여 4종의 시료를 제조하였으며, TLM을 이용한 저항을 측정하였다. 그 결과, 어닐링 조건이 콘택층의 저항과 소자의 전기적 안정성에 영향을 미치는 사실을 확인하였다.

• Composites Research
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• 제18권2호
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• pp.38-45
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• 2005

본 연구에서는 시차주사열량분석장치와 X-선 회절장치를 이용하여 어닐링 열처리 조건에 따른 니티놀 형상기억합금의 상변환 특성과 결정구조를 조사하였다. 어닐링 열처리 조건으로는 열처리 시간과 열처리 온도를 고려하였으며 특히 열처리 시간은 5분. 15분, 30분, 45분 그리고 열처리 온도는 $400^{\circ}C,\;500^{\circ}C,\;525^{\circ}C,\;550^{\circ}C,\;575^{\circ}C,\;600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$를 적용하였다 연구결과에 따르면 열처리 시간과 열처리 온도 등의 어닐링 열처리 조건은 니티놀 형상기억합금의 상변환 특성과 결정구조에 큰 영향을 미침을 알 수 있었다.

• 소성∙가공
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• 제28권6호
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• pp.354-360
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• 2019

The plastic strain ratio is one of the factors that affect the deep drawability of metal sheets. The plastic strain ratio of fully annealed Cu sheet is low because its texture has {001}<100>. In order to improve the deep drawability of Cu sheet, it is necessary to increase the plastic strain ratio of Cu sheet. This study investigate the increase of plastic strain ratio of a Cu sheet after the first asymmetry rolling and annealing, and the second asymmetry rolling and annealing in air and Ar gas conditions. The average plastic strain ratio (R_m) was 0.951 and |ΔR| value was 1.27 in the initial Cu sheet. After the second 30.1% asymmetric rolling and annealing of Cu sheet at 1000℃ in air condition, the average plastic strain ratio (R_m) was 1.03 times higher. However, |ΔR| was 0.12 times lower than that of the initial specimen. After the second 18.8% asymmetric rolling and annealing of Cu sheet at 630℃ in Ar gas condition, the average plastic strain ratio (R_m) was 1.68 times higher and |ΔR| was 0.82 times lower than that of the initial specimen. These results are attributed to the change of the texture of Cu sheet due to the different annealing conditions.

• Journal of information and communication convergence engineering
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• 제1권4호
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• pp.199-204
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• 2003

In this paper, we present the thermal annealing effects of the W/$SiO_2$ multi-layer reflectors in ZnO-based FBAR devices with cobalt (Co) electrodes in comparison with those with aluminum (Al) electrodes. Various thermal annealing conditions have been implemented on the W/$SiO_2$ multi-layer reflectors formed on p-type (100) silicon substrates. The resonance characteristics could be significantly improved due to the thermal annealing and were observed to depend strongly on the annealing conditions applied to the reflectors. Particularly, the FBAR devices with the W/$SiO_2$ multi- layer reflectors annealed at $400^{\circ}C$/30min have shown superior resonance characteristics in terms of return loss and quality-factor (Q-factor). In addition, the use of Co electrodes has resulted in further improvement of the resonance characteristics as compared with the Al electrodes. As a result, the combined use of both the thermal annealing and Co electrodes seems very useful to more effectively improve the resonance characteristics of the FBAR devices with the W/$SiO_2$ multi-layer reflectors.

• 열처리공학회지
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• 제31권2호
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• pp.56-62
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• 2018

Many researchers have studied on the precipitation control after solution treatment to improve the damping capacity without decreasing the strength. However, studies on the damping capacity and microstructure changes after deformation in the solid solution strengthening alloys were inadequate, such as the Al-Zn series magnesium alloys. Therefore, in order to investigate the effect of annealing condition on microstructure change and damping a capacity of AZ61 magnesium alloy. In this study, it was confirmed that the microstructure changes affect the damping capacity and hardness when annealed AZ61 alloy. AZ61 magnesium alloy was rolled at $400^{\circ}C$ with rolling reduction of 30%. These specimens were annealed at $350^{\circ}C$ to $450^{\circ}C$ for 30-180 minutes. After annealing, microstructure was observed by using optical microscopy, and damping capacity was measured by using internal friction measurement machine. Hardness was measured by Vickers hardness tester under a condition of 0.3 N. In this study, static recrystallization was observed regardless of the annealing conditions. In addition, uniform equiaxed grain structure was developed by annealing treatment. Hardness is decreased with increasing grain size. This is associated with Hall-Petch equation and static recrystallization. In case of damping capacity, bigger grain size show the larger damping capacity.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.708-712
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• 2004

Shallow $p^+-n$ junctions were formed by ion implantation and dual-step annealing processes. The dopant implantation was performed into the crystalline substrates using BF$_2$ ions. The annealing was performed with a rapid thermal processor and a furnace. FA+RTA annealing sequence exhibited better junction characteristics than RTA+FA thermal cycle from the viewpoint of junction depth and sheet resistance. A new simulator is designed to model boron diffusion in silicon. The model which is used in this simulator takes into account nonequilibrium diffusion, reactions of point defects, and defect-dopant pairs considering their charge states, and the dopant inactivation by introducing a boron clustering reaction. Using initial conditions and boundary conditions, coupled diffusion equations are solved successfully. The simulator reproduced experimental data successfully.

• 열처리공학회지
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• 제18권4호
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• pp.223-228
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• 2005

Tube hydroforming provides a number of advantages over conventional stamping process, including fewer secondary operation, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. It can produce wide range of products such as subframe, engine cradle, and exhaust manifold. In this study, the effect of the heat treatment conditions such as post seam annealing (PSA) and bright annealing (BA) on the ovality and hydro-formability of steel tubes has been investigated. Hydroformabilities have been estimated by the bulging heights obtained at various processing parameters such as internal pressure, axial feeding and heat treatment conditions. The ovality and forming height are strongly influenced by material properties after heat treatments.