• Title, Summary, Keyword: electrical conductivity

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The Effects of Solution Heat Treatment and Aging Treatment on the Electrical Conductivity and Hardness of Cu-Cr Alloys (크롬동합금의 도전율과 경도에 미치는 용체화처리와 시효처리의 영향)

  • Kim, Shin Woo
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.1
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    • pp.21-24
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    • 2002
  • The electrode materials for welding machine in automobile industry such as Cu-Cr, Cu-Zr and Cu-$Al_2O_3$ require the high electrical conductivity and the proper hardness. Therefore the effects of solution heat treatment and aging treatment on the electrical conductivity and hardness of Cu-0.8wt%Cr and Cu-1.2wt%Cr alloys have been investigated. Cu-0.8wt%Cr alloy showed the higher electrical conductivity and hardness than Cu-1.2wt%Cr alloy and both alloys showed the better electrical conductivity at $930^{\circ}C$ among 930, 980 and $1030^{\circ}C$ solution heat treatment temperatures. The electrical conductivity and hardness in both alloys were not affected by aging treatment but remarkably affected by solution heat treatment temperature. The final drawing process reduced electrical conductivity and increased hardness more in Cu-1.2wt%Cr alloy.

Effect of W Particle Size on the Electrical and Thermal Conductivity of W-Cu Composites (W 입자크기가 W-Cu 복합재료의 전기 및 열전도도에 미치는 영향)

  • 양주환;오승탁;박상우;문인형
    • Journal of Korean Powder Metallurgy Institute
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    • v.11 no.1
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    • pp.43-49
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    • 2004
  • The electrical and thermal conductivity of W-Cu composites were investigated as a function of the W-particle size and W-W contiguity. Powder mixtures were prepared by ball milling or mechanical alloying process, and then sintered at various temperatures. The electrical conductivity of sintered composite was increased with decreasing W grain size. Dependence of electrical conductivity on the W grain size was explained by the W-W contiguity concept. The thermal conductivity was increased with increasing the temperature up to $600^{\circ}C$ but decreased at the temperature above $600^{\circ}C$ Also, thermal conductivity value was influenced by the W particle size. Change of thermal conductivity in W-Cu composites was discussed based on the observed microstructural characteristics and theoretical considerations.

Electrical Conductivity of Chemically Reduced Graphene Powders under Compression

  • Rani, Adila;Nam, Seung-Woong;Oh, Kyoung-Ah;Park, Min
    • Carbon letters
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    • v.11 no.2
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    • pp.90-95
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    • 2010
  • Carbon materials such as graphite and graphene exhibit high electrical conductivity. We examined the electrical conductivity of synthetic and natural graphene powders after the chemical reduction of synthetic and natural graphite oxide from synthetic and natural graphite. The trend of electrical conductivity of both graphene (synthetic and natural) was compared with different graphite materials (synthetic, natural, and expanded) and carbon nanotubes (CNTs) under compression from 0.3 to 60 MPa. We found that synthetic graphene showed a marked increment in electrical conductivity compared to natural graphene. Interestingly, the total increment in electrical conductivity was greater for denser graphite; however, an opposite behavior was observed in nanocarbon materials such as graphene and CNTs, probably due to the differing layer arrangement of nanocarbon materials.

Applicability of Electrical Conductivity Monitoring Technique for Soil-bentonite Barrier (흙-벤토나이트월에 대한 전기전도도 모니터링 기법의 적용성 평가)

  • Oh, Myoung-Hak;Yoo, Dong-Ju;Kim, Yong-Sung;Park, Jun-Boum
    • Journal of the Korean Geotechnical Society
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    • v.23 no.7
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    • pp.47-55
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    • 2007
  • In this study, applicability of electrical conductivity monitoring technique for containment barrier such as soil-bentonite wall was evaluated. Laboratory tests including permeability tests and column tests were performed to understand variations in electrical conductivity at different bentonite contents, hydraulic conductivities, and heavy metal concentrations. The electrical conductivity of compacted soil-bentonite mixtures was found to increase proportionally with bentonite content. Accordingly, the hydraulic conductivity of compacted soil-bentonite mixtures which decreases linearly with increasing bentonite content was found to have an inversely proportional relationship with the electrical conductivity. In column tests, electrical conductivity breakthrough curves and concentration breakthrough curves were simultaneously obtained. These results indicated that electrical conductivity measurement can be an effective means of detecting heavy metal transport at the desired locations within barriers and verifying possible contaminant leakage. Experimental results obtained from this study showed that the electrical conductivity measurement can be a promising tool for monitoring of containment barrier.

Relationship Between Electrical Conductivity, Exchangeable Sodium Percentage and pH During Desalinization of Reclaimed Tidelands (간척지토양의 제염과정중 전기전도도와 치환성 나트륨 백분율 및 pH 사이의 관계)

  • 구자웅;은종호
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.30 no.4
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    • pp.127-133
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    • 1988
  • This study was performed to obtain the basic data analyzing salt movement and desalinization effects, and two different desalinization experiments through leaching and rinsing were carried out, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The relationships between the electrical conductivity of saturation extract and the electrical conductivity at various dilutions, and the correlations between electrical conductivity, total salt concentration, exchangeable sodium percentage and pH during the desalinization of reclaimed tidelands, were analyzed by the statistical method. The results obtained from this study were summarized as follows: 1.The sample soils used in this study were saline-sodic soils in accordance with the USDA classi- fication system of salt affected soils. 2.The electrical conductivity of saturation extract could be estimated conveniently, using the electrical conductivity of extract from various different soil-water suspensions. 3.The total salt concentration could be expressed in the electrical conductivity, but there was a little difference by soil textures. 4.The regression analysis showed that the relationship between the electrical conductivity of saturation extract and the exchangeable sodium percentage during the desalinization of reclaimed lands could be described by a linear regression equation. 5.The value of pH showed a tendency to increase according as the exchangeable sodium percentage decreased during the desalinization of reclaimed tidelands.

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Influence of P and Mg Additions on the Mechanical Properties and Electrical Conductivity of Cu-Sn Based Alloys (Cu-Sn계 합금의 기계적 성질과 전기전도도에 미치는 P 및 Mg 첨가의 영향)

  • Kim, Jeong-Min;Park, Joon-Sik;Kim, Ki-Tae
    • Journal of the Korean Society for Heat Treatment
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    • v.20 no.6
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    • pp.318-322
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    • 2007
  • The high electrical conductivity Cu-0.15% Sn alloys containing various P contents, and the high conductivity and high strength Cu-0.1% Sn-0.1%Ag alloys with various Mg/P additions were fabricated and their mechanical properties and electrical conductivity were investigated. The electrical conductivity was generally decreased as the P content was increased where as the hardness and strength was shown to increase. When Mg was added to P-containing Cu alloys, the detrimental effect of P on the conductivity was significantly reduced, and TEM observations indicated that the formation of $Mg_3P_2$ phase is responsible for this result.

Evaluation of Heat Treatment of an Al-Si Alloy forging by Using Its Relationship between Electrical Conductivity and Hardness (경도-전기전도도 상관관계를 이용한 A1-Si 알루미늄합금 열간 단조품의 열처리상태 평가)

  • 이석원;전만수;이준현
    • Transactions of Materials Processing
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    • v.10 no.5
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    • pp.418-424
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    • 2001
  • In this study, a relationship between hardness and electrical conductivity for an Al-Si aluminum alloy, forged after extruded, is investigated. Microvickers hardness is measured and compared with its corresponding electrical conductivity obtained by the eddy current test. It is found that a distinct relationship between the hardness and the electrical conductivity exists for the material. Using the relationship, the hardness of forging is predicted from the electrical conductivity obtained by eddy current test and the result is used to evaluate the condition of heat treatment.

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Effect of CuO and $Al_2O_3$ Addition on the Electrical Conductivity of ZnO (ZnO의 전기전도도에 미치는 CuO 및 $Al_2O_3$의 첨가영향)

  • 전석택;최경만
    • Journal of the Korean Ceramic Society
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    • v.32 no.1
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    • pp.106-112
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    • 1995
  • In order to examine the effect of CuO and Al2O3 addition on the electrical conductivity of ZnO, both Al2O3 (0, 1, 2, 5, 10at.%) and CuO (1, 5at.%) were added to ZnO. Al2O3 addition (~2at.% Al) increased the total electrical conductivity of ZnO which was already decreased by CuO doping effect Above solid solubility of Al (~2at.%), ZnAl2O4 formed and the total electrical conductivity decreased due to the decrease of sintered density. Impedance measurements were used to know the reason and degree of contribution of three resistive elements, ZnO grain, ZnO/CuO, and ZnO/ZnO grain boundaries, to the total electrical conductivity changed.

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Electrical Conductivity of YO$_{1.5}$-TaO$_{2.5}$-MgO Based Fluorite Phase (YO$_{1.5}$-TaO$_{2.5}$-MgO 계 Fluorite 상의 전기전도도)

  • Choi, Soon-Mok;Kim, Shin;Lee, Hong-Lim
    • Journal of the Korean Ceramic Society
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    • v.35 no.5
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    • pp.521-527
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    • 1998
  • Electrical conductivity of fluorite structure phases in the {{{{ {Y }_{0.8 } }}{{{{ { Ta}_{ 0.2} {O }_{1.7 }-MgO }} system has been studied. Electrical conductivity of 8mol% MgO doped {{{{ {Y }_{0.8 } }} {{{{ {Ta }_{0.2 } {O }_{1.7 } }} fluorite phase was lower than that of the undoped {{{{ {Y }_{0.8 } }}{{{{ {Ta }_{0.2 } {O }_{1.7 } }} When {{{{ { P}_{H2O } }} was increased electrical conductivity of {{{{ {Y }_{0.8 } }}{{{{ {Ta }_{0.2 } {O }_{1.7 } }} increased linealy with {{{{ { P}`_{H2O } ^{ {1 } over {2 } } }} The {{{{ {Y }_{0.8 } }}{{{{ {Ta }_{0.2 } {O }_{1.7 } }} fluorite phase exhibited higher electrical conductivity in wet atmosphere than in dry atmosphere. The identical trend was observed from the 8mol% MgO doped {{{{ {Y }_{0.8 } }}{{{{ {Ta }_{0.2 } {O }_{1.7 } }} fluorite phase.

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Evaluation of Mechanical Compressive Properties of Al-Si-Cu-Mg Alloy Foams Using Electrical Conductivity (전기전도도를 이용한 Al-Si-Cu-Mg 합금 품의 기계적 압축 특성 평가)

  • Lee, Chang-Hun;Kim, Am-Kee;Ha, San;Nahm, Seung-Hoon;Cho, Seong-Seock
    • Proceedings of the KSME Conference
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    • pp.377-381
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    • 2004
  • Electrical conductivity of Al-Si-Cu-Mg alloy foams of various density produced in powder metallurgical method has been measured using two probe electrical conductivity measurement method. Compressive mechanical properties such as elastic modulus and plastic plateau stress of foams were evaluated from electrical conductivity using power law relation and scaling laws of foam properties. Uni-axial compression test was also performed. Experimentally measured elastic modulus and plastic plateau stress were compared with the values evaluated from electrical conductivity. The computed values were in good agreement with the experimental result.

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