• Corrosion Science and Technology
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• 제11권6호
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• pp.280-285
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• 2012

Aluminum is on active metal, but it is well known that its oxide film plays a role as protective barrier which is comparatively stable in air and neutral aqueous solution. Thus, aluminum alloys have been widely applied in architectural trim, cold & hot-water storage vessels and piping etc., furthermore, the aluminum alloy of AC8A have been widely used in mold casting material of engine piston because of its properties of temperature and wear resistance. In recent years, the oil price is getting higher and higher, thus the using of low quality oil has been significantly increased in engines of ship and vehicle. Therefore it is considered that evaluation of corrosion resistance as well as wear resistance of AC8A material is also important to improve its property and prolong its lifetime. In this study, the effect of solution and tempering heat treatment to corrosion and wear resistance is investigated with electrochemical method and measurement of hardness. The hardness decreased with solution heat treatment compared to mold casting condition, but its value increased with tempering heat treatment and exhibited the highest value of hardness with tempering heat treatment temperature at $190^{\circ}C$ for 24hrs. Furthermore, corrosion resistance increased with decreasing of the hardness, and decreased with increasing of the hardness reversely. As a result, it is suggested that the optimum heat treatment to improve both corrosion and wear resistance is tempering heat treatment temperature at $190^{\circ}C$ for 16hrs.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.109-114
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• 2000

본 연구에서는 전파흡수체용 ferrite-Rubber Composite에서 Ferrite의 열처리 온도와 Composite의 전파흡수특성과의 상관관계에 관하여 알아보았다. 이때 Ferrite는 스피넬 구조의 형성과 결정입의 비교적 큰 성장을 위하여 1100, 1200, 1300 $^{\circ}C$에서 각각 2시간 열처리 처리하였다. 열처리 온도를 달리하여 제조한 Ferrite-Rubber Composite는 A가 Mn인 경우에는 열처리 온도가 높을수록 반사감쇠량이 작아지는 경향을 보였다. 그러나 A가 Cu와 Mg인 경우 열처리 은도가 높을수록 페라이트의 반사감쇠량이 커지는 경향을 보였다. 이로부터 전파흡수체용 Ferrite는 화학조성에 따라서 적정 열처리 온도가 존재함을 알 수 있었다.

• 동력기계공학회지
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• 제17권4호
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• pp.72-78
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• 2013

Compacted graphite iron 340 was carried out the heat treatment from 873 to 1,273 K. Compacted graphite iron 340 was evaluated relationship between the sound velocity, the attenuation coefficient and the tensile strength. The obtained results are as following. The signal strength of C scan images were weak according to increasing of heat treatment temperature and time. The amplitude of A scan and B scan was also low. This can be cause that the graphite was grown into the type of vermicular, and the many of grain boundary with ultrasound scattering were increase. The sound velocity was depend upon the heat treatment temperature and time, the attenuation coefficient had nothing to do with the temperature and time. The higher the heat treatment temperature, the tensile strength and the sound velocity were decreased. However, the tensile strength was proportional to the sound velocity. The higher tensile strength, the faster the sound velocity.

• 한국산학기술학회논문지
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• 제15권3호
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• pp.1795-1800
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• 2014

본 논문은 생물학적 활성오니 폐수처리공정의 열전달 모델식을 제시하여 공정의 온도를 예측하였다. 열전달 모델은 폐수처리공정에 들어오고 나가는 모든 열을 고려하였다. 공정에 들어오는 열은 태양 복사열과 포기조 impeller의 기계적 에너지의 변환열, 포기조 내의 생화학 반응열이다. 공정에서 나가는 열은 폐수 자체의 복사열, 포기작용에 의한 증발열과 포기조 표면으로 나가는 전도열, 바람에 의한 대류열, 포기조와 지표면과의 전도열을 고려하였다. 들어오고 나가는 모든 열은 기존의 열전달 경험식을 적용하였다. 적용된 경험식으로 폐수처리장 공정의 열전달 모델식을 제시하였다. 모델식으로 실제 폐수처리공정의 온도를 예측하였으며, 모델식 예측치와 실제값이 $1.0^{\circ}C$ 이내로 일치하였다.

• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.101-107
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• 2010

Heat treatment was performed to improve sound absorption properties for four tree species; Tulip tree, Korean Paulownia, Red pine and Costata birch, at temperature of $175^{\circ}C$ and $200^{\circ}C$under vacuum condition. Sound absorption properties of two kinds of boards, which were in radial and tangential sections, were measured under a frequency range of 100 to 3200 Hz by the two microphone transfer function method. It was found that sound absorption properties were increased by heat treatment and the efficiency was higher at $200^{\circ}C$ than that at $175^{\circ}C$. Even Costata birch had a little effect on low temperature of $175^{\circ}C$, $200^{\circ}C$ heat treatment for sound absorption property, the efficiencies of sound absorption were 14, 19%, respectively. The efficiencies of sound absorption ranged 22 to 120% for heat-treated Tulip tree, Korean Paulownia.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.258-263
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• 2000

River water is higher in temperature than the surrounding environment during the winter. It is highly suitable a heat source for heat pump system. Despite its suitability, however, it is not widely used, due to its fouling and corrosive nature in heat exchanger tubes of evaporator. It is designed prior-treatment system which come into direct contact with the river water, such as auto-seamer, ozone generator for bactericidal test and auto-cleaning system. And it is analyzed treatment effects for its operation. It is designed two-stage compression heat pump system using R-134a with heating load 35.16kW, ad analyzed its performance. As a result it is obtained 3.08 COP when mid-point pressure is 1,200kPa, and bypass ratio of flowing refreigerant to high-stage compressor is 25.1%

• 반도체디스플레이기술학회지
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• 제12권4호
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• pp.39-44
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• 2013

In the semiconductor heat-treatment process, the temperature uniformity determines the film quality of a wafer. This film quality effects on the overall yield rate. The heat transfer of the wafer surface in the heat-treatment process equipment is occurred by convection and radiation complexly. Because of this, there is the nonlinearity between the wafer temperature and reactor. Therefore, the accurate prediction of temperature on the wafer surface is difficult without the direct measurement. The thermal camera and the T/C wafer are general ways to confirm the temperature uniformity on the heat-treatment process. As above ways have limit to measure the temperature in the precise domain under the micro-scale. In this study, we developed the thin film type temperature sensor using the MEMS technology to establish the system which can measure the temperature under the micro-scale. We combined the experiment and numerical analysis to verify and calibrate the system. Finally, we measured the temperature on the wafer surface on the semiconductor process using the developed system, and confirmed the temperature variation by comparison with the commercial T/C wafer.

• 청정기술
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• 제28권2호
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• pp.110-116
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• 2022

본 연구에서는 NdFeB 영구자석 스크랩으로부터 회수한 철(Fe) 부산물을 이용하여 산화철(FeO_x) 나노입자를 합성하였고, 열처리 온도가 FeO_x 나노입자의 물성에 미치는 영향을 관찰하였다. 이를 위해 D.I. water에 약 10 wt%로 희석한 철 부산물 용액에 2.0 M 암모니아(NH₄OH) 용액을 투여하여 산화철 전구체를 석출하였고, 이를 300 ℃, 400 ℃, 500 ℃ 및 600 ℃로 각각 열처리하여 FeO_x 나노 입자를 합성, 열처리 온도에 따른 FeO_x 나노 입자의 물성을 관찰하였다. X-ray diffraction (XRD) 분석 결과 열처리 온도가 증가할수록 <104> 회절 피크가 성장하여 500 ℃ 이상에서 α-Fe₂O₃ 결정구조와 일치하는 회절 피크가 검출되었다. BET (Brunauer-Emmett-Teller) 비표면적 분석 결과 400 ℃ 이상에서 열처리 온도가 증가할수록 비표면적이 감소하는 경향을 나타내었다. HRTEM (high resolution transmission electron microscope) 관찰 결과 rod 형 나노입자가 관찰되었고, 열처리 온도 증가에 따라 나노입자의 크기가 증가하는 경향을 나타내었다.

• 한국염색가공학회지
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• 제25권3호
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• pp.206-214
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• 2013

There has been an increasing demand for high performance and energy-saving of blind. In order to develop the eco-friendly blind textiles, heat treatment process has been utilized for LM(Low Melting) polyester fabrics and the changes of the physical properties of the treated fabrics were examined according to temperature of heat treatment. Morphology, surface reflectance, contact angle, luster, thermal property and mechanical property of heat treated LM polyester fabrics were investigated. As results, morphology analysis of thermal treated fabrics confirmed that degree of fusion of LM polyester yarns improved with increase of temperature. Surface reflectance of thermal treated fabrics decreased with increase of temperature. Luster and contact angle of a water droplet on thermal treated fabrics increased slightly with increase of temperature. The mechanical properties of the fabrics by KES-FB system were found to be temperature-dependent and especially, bending and shear properties among them were highly related to temperature.

• 열처리공학회지
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• 제6권4호
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• pp.223-229
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• 1993

Extensive reseach has been performed on the process condition-micro structure-stress relations of TiN film. The various proposed models are mainly base on physical vapor deposition processes. Especially the study on the micro-structure and deposition condition has not been sufficient in TiN deposited by PECVD. In this study, therefore, we discussed the morphological changes of TiN films by PECVD with different temperature and pressure, and compared it with the structure zone model. We could find out that the oxygen and chlorine contents and the texture coefficient increased with deposition temperature, and the morphology of TiN transformed from Zone 1 to Zone T, but deposition pressure didn't remarkly affected.