• Title/Summary/Keyword: High temperature XRD

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Examination of Ingredients of High Temperature Heat Resistant Inorganic Fire-Resistant Adhesive Using XRD Analysis (XRD 분석을 이용한 고온가열 무기계 내화 접착제의 성분검토)

  • Cho, Hyeon-Seo;Ji, Woo-Ram;Shin, Ki-Don;Lee, Gun-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.81-82
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    • 2018
  • The structure of the RC structure is actively reinforcing the structure of the building which has suffered from aging, artificial and natural damage of the building. Among various reinforcement methods, epoxy adhesive is used to attach FRP in FRP reinforcement method which is reinforcing by attaching FRP to the structural part. At this time, the epoxy adhesive having a low critical temperature has a sudden adhesive failure upon exposure to heat, and thus, the development of an inorganic fireproof adhesive having a high critical temperature has progressed. Therefore, in this study, the compositional change of inorganic fire - resistant adhesive exposed to high temperature heat was analyzed by XRD.

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Estimation Study of Firing Temperature for Fired Clay Brick Relics Excavated from Buddhist Temple in Karatepa Using Analytical Method of High Temperature X-ray Diffraction (고온 XRD 분석법을 이용한 카라테파 불교사원 출토 점토벽돌의 소성온도 추정연구)

  • Han, Min Su;Lee, Jang Jon;Kim, Jae Hwan
    • Journal of Conservation Science
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    • v.32 no.4
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    • pp.511-520
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    • 2016
  • The purpose of this study was to estimate the firing temperature of fired clay brick by applying high temperature X-ray diffraction(XRD) analysis. The clay bricks, which were excavated from a Buddhist temple in Karatepa, Uzbekistan were composed of quartz, plagioclase, alkali feldspar, mica, chlorite, limestone, hornblende, etc. Some clay bricks contained gypsum, which was presumed to have been used to improve the adhesive strength of the brick. Estimating the firing temperature using a geologic thermometer, the UZ-1 sample was identified as being in the quartz, plagioclase, pyroxene series, and the firing temperature was estimated to be $900-1200^{\circ}C$. On the other hand, applying the high temperature XRD method to the UZ-5 sample, it was found that the limestone was destroyed at $1000^{\circ}C$ and the diffraction peak of chlorite was weakened at $1050^{\circ}C$. Moreover, pyroxene series minerals developed at $1050^{\circ}C$ in the reproduction experiment. These results indicate that the clay bricks used in the temple were produced in a kiln that reached a temperature of more than $1000^{\circ}C$. Thus, high temperature XRD analysis can more accurately estimate firing temperatures as compared to the firing temperature mineral identification method and it can be used to determine the creation and extinction temperature range of minerals.

Performance Evaluation of High Strength Concrete with Composite Fibers in Accordance with High Temperature (복합섬유가 혼입된 고강도 콘크리트의 고온가열에 따른 성능 평가)

  • Kim, Seung-Ki;Kim, Woo-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.6
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    • pp.63-71
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    • 2015
  • The objective of the present study is to investigate how elevated temperature ranging from $100^{\circ}C$ to $800^{\circ}C$ as well as room temperature affects the variation of mechanical properties of high strength concrete ($over\;f_{ck}=60MPa\;grade$). In this experiment, specimens were exposed for a period of $2^{\circ}C/min$ to temperatures of $20^{\circ}C$, $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$ $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$ and $800^{\circ}C$, respectively. Accordingly, the study investigated the fire resistance performance of high strength concrete mixed with composite fibers which composed with hybrid fibers and steel fibers. After cooling down to ambient temperature, the following basic mechanical properties were then evaluated and compared with reference values obtained prior to thermal exposure: (i) compressive strength in room temperature; (ii) residual compressive strength; (iii) Poisson's ratio; (iv) weight change; (v) SEM analysis & XRD analysis In addition, XRD and SEM Images analyses were performed to investigate chemical and physical characteristics of high strength concrete with composite fibers according to high temperature.

Microstructure Properties of Cement Matrix Exposed to High Temperature (고온에 노출 된 시멘트 매트릭스의 미세구조 특성)

  • Lee, Gun-Young;Lee, Gun-Cheol;Choi, Jung-Gu;Gao, Shan;Heo, Young-Sun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.11a
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    • pp.24-25
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    • 2015
  • To secure fundamental materials for the performance change in concrete structure damaged by fire, this study analyzed SEM and XRD of hardened cement depending on high temperature conditions. As a result, at more than 200℃, SEM and XRD were not observed because of dehydration of Ettringite; at more than 500℃, calcium hydroxide was rapidly decomposed; at more than 700℃, calcium oxide was found; at 1000℃, the highest peak point appeared.

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A Study on the Degradation of Mechanical Properties in High Nitrogen Steel Following Heat Treatments and Welding (고질소계 강의 열처리재 및 용접부의 기계적성질 저하에 관한 연구)

  • 권일현;윤재영;정세희
    • Journal of Welding and Joining
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    • v.16 no.3
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    • pp.121-128
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    • 1998
  • The degradation of mechanical properties in the high nitrogen steel HN3 developed for nuclear fusion reactor has been evaluated quantitatively using the small punch(SP) test, X-ray diffraction (XRD) analysis has also been conducted to identify carbides or nitrides precipitated on grain boundaries of the heat treated samples. Mechanical properties of the steel HN3 significantly decreased with increasing heat treatment time and temperature or with decreasing testing temperature. Combination of XRD and metallurgical observation, revealed that the material degradation in the thermally aged steel was caused by precipitation of carbides on the grain boundaries. While the weld metal showed the lowest mechanical properties among various microstructures in GTA weldments. By combining SP test and XRD analysis, cryogenic fracture behaviors and aging degradation for high nitrogen steel could be successfully evaluated in nondestructive manner.

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Evaluation of Failure Mechanism of Flexible CIGS Solar Cell Exposed to High Temperature and Humid Atmosphere (플렉서블 CIGS 태양전지의 고온고습 환경 고장 기구 분석)

  • Kim, Hyeok-Soo;Byeon, Jai-Won
    • Journal of Applied Reliability
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    • v.16 no.1
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    • pp.41-47
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    • 2016
  • Purpose: The purpose of this study was to evaluate electrical and structural degradation of flexible CIGS sollar cell exposed to high temperature and humid atmosphere. Method: Accelerated degradation was performed for various time under $85^{\circ}C/85%RH$ and then electrical and structural properties were analyzed by 4-point probe method, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results: Sheet resistance of the top ITO layer increased with exposure time to the high temperature and humid atmosphere. Blunting of the protrusion morphology of ITO layer was observed for the degraded specimen, while no phase change was detected by XRD. Oxygen was detected at the edge area after 300 hours of exposure. Conclusion: Increase in electrical resistance of the degraded CIGS solar cell under high temperature and humid environment was attribute to the oxygen or water absorption.

Self-Cleaning and Photocatalytic Performance of TiO2 Coating Films Prepared by Peroxo Titanic Acid

  • Yadav, Hemraj M.;Kim, Jung-Sik
    • Korean Journal of Materials Research
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    • v.27 no.11
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    • pp.577-582
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    • 2017
  • Self-cleaning and photocatalytic $TiO_2$ thin films were prepared by a facile sol-gel method followed by spin coating using peroxo titanic acid as a precursor. The as-prepared thin films were heated at low temperature($110^{\circ}C$) and high temperature ($400^{\circ}C$). Thin films were characterized by X-ray diffraction(XRD), Field-emission scanning electron microscopy(FESEM), UV-Visible spectroscopy and water contact angle measurement. XRD analysis confirms the low crystallinity of thin films prepared at low temperature, while crystalline anatase phase was found the for high temperature thin film. The photocatalytic activity of thin films was studied by the photocatalytic degradation of methylene blue dye solution. Self-cleaning and photocatalytic performance of both low and high temperature thin films were compared.

Microstructure Characteristics of Concrete Exposed to High Temperature (고온에 노출된 콘크리트 미세조직의 특성)

  • 태순호;이병곤
    • Fire Science and Engineering
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    • v.12 no.4
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    • pp.31-40
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    • 1998
  • Very often, whether accidentally or intentionally set fire, according as building are elevated, varied or complicated day by day. It is of primary importance that we have a treatment of fire damaged structure. In general, strength and elasticity modulus of heated concrete are reduced. Product background of cement, sand and coarse aggregate differ from country to country, so that thermal behaviour of concrete make a difference in high temperature. To cope with demand, this paper is a study on relation to microstructure and strength reduction. In consequence of experiments, concrete exposed to high temperature are estimating the reduction of mechanical properties in comparison with microstructure characteristics which are abtained from the SEM/EDX, XRD and DSC-TG analysis of heated specimens under various temperature.

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A Structural Study of the Oxidized High Modulus Pitch Based Carbon Fibers by Oxidation in Carbon Dioxide

  • Roh, Jae-Seung
    • Carbon letters
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    • v.5 no.1
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    • pp.27-33
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    • 2004
  • Structural changes of high modulus carbon fiber by oxidation in carbon dioxide gas using SEM, TEM, and XRD have been observed. It was shown that the originally high modulus carbon fiber is composed of highly ordered graphitic crystalline area and non-crystalline area. It was observed that the La increases during the whole oxidation process. It was shown that the oxidation of high modulus carbon fiber initiates at the non-crystalline area and at the ends of fiber. The large pores developed in fiber by direction of fiber length at high temperature ($1,100^{\circ}C$), and the small pores developed on the fiber surface at low temperature ($900^{\circ}C$). In conclusion, it is found that the oxidation of the carbon fiber was progressed through the imperfection.

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Analysis of Electrical Characteristics of Oxide Semiconductor of ZnO, SnO2 and ZTO (ZnO, SnO2, ZTO 산화물반도체의 전기적인 특성 분석)

  • Oh, Teresa
    • Korean Journal of Materials Research
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    • v.25 no.7
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    • pp.347-351
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    • 2015
  • To study the characteristics of ZTO, which is made using a target mixed $ZnO:SnO_2=1:1$, the ZnO and $SnO_2$ were analyzed using PL, XRD patterns, and electrical properties. Resulting characteristics were compared with the electrical characteristics of ZnO, $SnO_2$, and ZTO. The electrical characteristics of ZTO were found to improve with increasing of the annealing temperature due to the high degree of crystal structures at high temperature. The crystal structure of $SnO_2$ was also found to increase with increasing temperatures. So, the structure of ZTO was found to be affected by the annealing temperature and the molecules of $SnO_2$; the optical property of ZTO was similar to that of ZnO. Among the ZTO films, ZTO annealed at the highest temperature showed the highest capacitance and Schottky contact.