• Title/Summary/Keyword: sheath alloying

Search Result 10, Processing Time 0.024 seconds

Effects of Ag-alloy sheath on thermal/electrical conductivity of Bi-2223 superconductor tapes (피복합금을 사용한 Bi-2223 선재의 열전도도 및 전기전도도 특성평가)

  • ;;;;;John Slavko Volf;Hua Kun Liu;Miles Apperley
    • Progress in Superconductivity
    • /
    • v.4 no.2
    • /
    • pp.180-183
    • /
    • 2003
  • We evaluated the effect of alloying-element additions to Ag sheath on thermal conductivity of Bi-2223 superconductor tapes. In order to evaluate the effect of sheath alloys and their configuration on the properties of tape, various combinations of Ag and Ag alloys were selected as inner and outer sheath. Thermal conductivity of the tapes was measured by using thermal integral method at 10∼120 K. It is observed that the presence of alloying-elements such as Mg, Sb, and Au in Ag sheath results in decreased thermal conductivity at low temperature. Specifically, the thermal conductivity of AgMg, AgSb, and AgAu at 40 K were 411.4, 142.3, and 109.7 W/(m·K), respectively, which is about 2∼9 times lower than that of Ag (1004.6 W/(m·K)). In addition, the thermal conductivity of alloy-sheathed tape was significantly dependent on their values of constituent sheath materials.

  • PDF

The Effects of Alloying-Element Additions to Ag Sheath on Thermal Conductivity and Properties of Bi-2223 Superconductor Tapes (합금원소 첨가에 따른 Ag 피복 Bi-2223 초전도 선재의 열전도도 측정 및 특성평가)

  • ;;;;;;John Slavko Volf;Hua Kun Liu;Miles Apperley
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.16 no.7
    • /
    • pp.627-633
    • /
    • 2003
  • The effects of alloying-element additions to Ag sheath on thermal conductivity and mechanical properties of Bi-2223 superconductor tapes have been evaluated. In order to evaluate the effects of sheath alloys and their configuration on the properties of tape, various combinations of Ag and Ag alloys were selected as the inner and outer sheath. Thermal conductivity of the tapes was evaluated by using thermal integral method at 10 ∼120 K. It was observed that the addition of Mg, Sb, and Au to Ag sheath significantly decreased the thermal conductivity at low temperature probably due to the alloying effect. Specifically, the thermal conductivity of AgMg, AgSb, and AgAu at 40 K were 411.4, 142.3, and 109.7 W/(m·K), respectly, which is about 2∼9 times lower than that of Ag (1004.6 W/(m·K)). In addition, the thermal conductivity of alloy-sheathed tape was significantly dependent on their thermal conductivities of constituent sheath materials. The mechanical properties of alloy-sheathed tapes were also evaluated. Yield strength and tensile strength were improved but workability decreased for alloy-sheathed tapes.

Mechanical properties at Bi-2223 HTS tapes with various sheath materials (기지금속을 달리한 Bi-2223 초전도 선에서의 기계적 특성 변화)

  • Ha, Dong-Woo;Lee, Dong-Hoon;Yang, Joo-Sang;Kim, Sang-Chul;Hwang, Sun-Yuk;Ha, Hong-Soo;Oh, Sang-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2004.07a
    • /
    • pp.551-554
    • /
    • 2004
  • Bi-2223 HTS tapes are used widely for application of superconducting power systems. However there are need the properties of high strength and low AC loss. Two kinds of Bi-2223 HTS tapes with different Ag sheath were used to know the effect of sheath alloying for the strength and the resistivity. The workability and reaction degree of superconducting phase at Bi-2223 HTS tapes were investigated. We designed conventional type-Ag/alloy and double sheathed mono filament type-Ag/alloy/alloy in order to increase the strength and resistivity of matrix in Bi-2223 HTS tapes. The effect of axial strain and thermal cycling on the critical current was investigated for the Bi-2223 HTS tapes. Because the workability of double sheath Bi-2223 HTS tape was lower than one sheath Bi-2223 HTS tape, it was need additional softening treatment. Bi-2223 formation reaction was decreased by Ag alloy matrix during sintering process. Two kinds of Bi-2223/Ag tapes with different Ag sheath were used to know the effect of sheath alloying for the tensile strain. Critical current is drastically decreased for Ag/alloy and Ag/alloy/alloy sheathed tapes at tensile strain above 0.24 % and 0.34 %, respectively. This result showed that mechanical strength was increased over than 40 % by introduce double sheath at mono filament stage.

  • PDF

Mechanical and Thermal Properties of Ag sheath alloys for Bi-2223 superconductor tape

  • Kim, Tae-Woo;Joo, Jin-Ho;Nah, Wan-Soo;Yoo, Jai-Moo;Ko, Jae-Woong;Kim, Hai-Doo;Chung, Hyung-Sik;Lee, Sang-Hyun
    • Progress in Superconductivity
    • /
    • v.1 no.1
    • /
    • pp.61-67
    • /
    • 1999
  • We evaluated the effect of alloying element additions to Ag sheath on mechanical, electrical and thermal properties of Bi-2223. Additions of Au, Pd and Mg to Ag sheath increased hardness and strength, while reduced elongation and electrical and thermal conductivity. In addition, microstructural investigation showed that the grain size of Ag significantly decreased with increasing content of alloying elements. The improvements in strength and hardness are believed to be due to the presence of alloying elements that lead to strengthen materials by combined effects of solid-solution, dispersion hardening and grain size hardening. Thermal conductivity of Ag and Ag alloys was evaluated in the temperature range from 77 K to 300 K, and com-pared to calculated value obtained by Wiedermann-Franz law. It was observed that the thermal conductivity decreased with increasing the content of alloying elements. Specifically, the thermal conductivity of $Ag_{0.92}Pd_{0.06}Mg_{0.02}$ alloy was measured to be $48.2W/(m{\cdot}K)$ at 77 K, which is about 6 times lower than that of $Ag(302.6W/(m{\cdot}K))$.

  • PDF

Thermal conductivity and properties of sheath alloy for High-$T_c$ superconductor tape (고온초전도 선재용 피복합금의 열전도도 측정 및 특성평가)

  • 박형상;지봉기;김중석;임준형;오승진;오승진;주진호;나완수;유재무
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.13 no.8
    • /
    • pp.711-717
    • /
    • 2000
  • Effect of alloying element additions to Ag on thermal conductivity electrical conductivity and mechanical properties of sheath materials for BSCCO tapes has been characterized. The thermal conductivity at low temperature range(10~300K) of Ag alloys were evaluated by both direct and indirect measurement techniques and compared with each other. It was observed that thermal conductivity decreased with increasing the content of alloying elements such as Au, Pd and Mg. Thermal conductivity of pure Ag at 30 K was measured to be 994.0 W/m.K on the other hand the corresponding values of A $g_{0.9995}$/M $g_{0.0005}$, A $g_{0.974}$/A $u_{0.025}$/M $g_{0.001}$, A $g_{0.973}$/Au.0.025//M $g_{0.002}$, and A $g_{0.92}$/P $d_{0.06}$/M $g_{0.02}$ were 342.6, 62.1, 59.2, 28.9 W/m.K respectively indicating 3 to 30 times lower than that of pure Ag. In addition alloying element additions to Ag improved mechanical strength while reduced elongation probably due to the strengthening mechanisms by the presence of additive atoms.s.

  • PDF

Dependence of thermal cycling and axial strain on HTS PIT tapes (고온초전도 PIT선재의 반복 열응력 및 변형률 의존성)

  • 하홍수;이동훈;최정규;양주생;황선역;김상철;하동우;오상수;권영길
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • 2003.10a
    • /
    • pp.131-133
    • /
    • 2003
  • The effect of axial strain and thermal cycling on the critical current is investigated for the Bi-2223/Ag PIT tapes. The axial strain was applied to the tapes by the U-shape sample holder. Two kinds of Bi-2223/Ag tapes with different Ag sheath are used to know the effect of sheath alloying for the tensile strain. The influence of thermal cycling between room temperature and 77 K on critical current are examined. Critical current is drastically decreased for Ag/alloy and Ag/alloy/alloy sheathed tapes at tensile strain above 0.22% and 0.3%, respectively.

  • PDF

Low Temperature Thermal Conductivity of Sheath Alloys for High $T_{c}$ Superconductor Tape

  • Park, Hyung-Sang;Oh, Seung-Jin;Jinho Joo;Jaimoo Yoo
    • Transactions on Electrical and Electronic Materials
    • /
    • v.1 no.2
    • /
    • pp.32-37
    • /
    • 2000
  • Effect of alloying element additions to Ag on thermal conductivity and electrical conductivity of sheath materials for Bi-Pb-Sr-Ca-Cu-O(BSCCO) tapes has been characterized. The thermal conductivity at low temperature range (10~300K) of Ag and Ag alloys were evaluated by both direct and indirect measurement techniqueas and compared with each other, It was observed that the thermal conductivity decreases with increasing the content of alloying element such as Au, Pd and Mg. Thermal conductivity of pure Ag at 3 0K was measured to be 994.0 W(m.K) on the other hand, the corresponding values of $Ag_{0.9995}Mg_{0.0005}$, $Ag_{0.974}$, $Au_{0.025}$, $Mg_{0.001}$, $Ab_{0.973}$, $Au_{0.025}$, $Mg_{0.002}$ and $Ag_{0.92}$, $Pb_{0.06}$, $Mg_{0.02}$ were 342.6, 62.1, 59.2 and 28.9 W(m.K), respectively, indicating 3 to 30 times lower than that of pure Ag. In addition, the thermal conductivity of pure Ag measured by direct and indirect measurement techniques was 303.2 and 363.8 W(m.K) The difference in this study is considered to be within an acceptable error range compared to the reference data.

  • PDF

Effect of External Reinforcement on Stress/strain Characteristics of Critical Current in Ag Alloy Sheathed Bi-2212 Superconducting Tapes (Bi-2212 초전도 테이프에서 임계전류의 응력/변형률 특성에 미쳐는 외부강화의 영향)

  • ;K. Katagiri
    • Progress in Superconductivity and Cryogenics
    • /
    • v.3 no.1
    • /
    • pp.6-10
    • /
    • 2001
  • Stress/stram dependencies of the critical current $I_c$ in AgMgNi sheathed multifilamentary Bi(2212) superconducting tapes were evaluated at 77K, 0T. The external reinforcement was accomplished by soldering Ag-Mg tapes to sin91e side or both sides of the sample. With the external reinforcement. the strength of tapes increased but $I_c$, decreased The $I_c$, degradation characteristic according to the external reinforcement was improved markedly in terms of the stress although it appeared less rectal.table on the basis of the strain. Effects of external reinforcement were discussed in a viewpoint of monitoring sensitivity of cracking in superconducting filaments by considering n-value representing the transport behavior of the current. It is closely associated with the location of them relative to the voltage-monitoring region in the tape.

  • PDF

Improvement of Jc for Ag alloy Sheathed Bi-2223 HTSC Tape (은 합금 시스 Bi-2223 고온초전도 테이프의 임계전류밀도 향상)

  • Jang, H.M.;Oh, S.S.;Ha, D.W.;Ryu, K.S.;Kim, S.H.
    • Proceedings of the KIEE Conference
    • /
    • 1996.07c
    • /
    • pp.1489-1491
    • /
    • 1996
  • The effect of Ag alloy sheath have been investigated in terns of critical current density and mechanical property. Nevertheless the continuous improvement of critical current density($J_c$) of Ag sheathed Bi2223 oxide superconducting wire processed with powder in tube(PIT) method, poor mechanical strength is still considered to be demerits for power application. In this study, we prepared two kinds of Ag- x wt% Cu alloy and pure Ag sheathed Bi2223 superconducting tapes. The hardness and tensile strength of prepared tapes has been measured. Their mechanical propertes were improved by Ag alloying.

  • PDF

Jangdo(Small Ornamental Knives) manufacturing process and restoration research using Odong Inlay application (오동상감(烏銅象嵌)기법을 활용한 장도(粧刀)의 제작기술 및 복원연구)

  • Yun, Yong Hyun;Cho, Nam Chul;Jeong, Yeong Sang;Jang, Chu Nam
    • Korean Journal of Heritage: History & Science
    • /
    • v.49 no.2
    • /
    • pp.172-189
    • /
    • 2016
  • In this research, literature research on the Odong material, mixture ratio, casting method and casting facility was conducted on contemporary documents, such as Cheongong Geamul. Also, a long sword was produced using the Odong inlay technique. The sword reproduction steps were as follows; Odong alloying, silver soldering alloying, Odong plate and Silver plate production, hilt and sheath production, metal frame and decorative elements, such as a Dugup (metal frame), production, Odong inlay assembly and final assembly. For the Odong alloy production, the mixture ratio of the true Odong, which has copper and gold ratio of 20:1, was used. This is traditional ratio for high quality product according to $17^{th}$ century metallurgy instruction manual. The silver soldering alloy was produced with silver and brass(Cu 7 : Zn 3) ratio of 5:1 for inlay purpose and 5:2 ratio for simple welding purpose. The true Odong alloy laminated with silver plate was used to produce hilt and sheath. The alloy went through annealing and forging steps to make it into 0.6 mm thick plate and its backing layer, which is a silver plate, had the matching thickness. After the two plates were adhered, the laminated plate went through annealing, forging, engraving, silver inlaying, shaping, silver welding, finishing and polishing steps. During the Odong colouring process, its red surface turns black by induced corrosion and different hues can be achieved depending on its quality. To accomplish the silver inlay Odong techniques, a Hanji saturated with thirty day old urine is wrapped around a hilt and sheath material, then it is left at warm room temperature for two to three hours. The Odong's surface will turn black when silver inlay remains unchanged. Various scientific analysis were conducted to study composition of recreated Odong panel, silver soldering, silver plate and the colouring agent on Odong's surface. The recreated Odong had average out at Cu 95.57 wt% Au 4.16wt% and Cu 98.04 wt% Au 1.95wt%, when documented ratio in the old record is Cu 95wt% and Au 5wt%. The recreated Odong was prone to surface breakage during manufacturing process unlike material made with composition ratio written in the old record. On the silver plate of the silver and Odong laminate, 100wt% Ag was detected and between the two layers Cu, Ag and Au were detected. This proves that the adhesion between the two layers was successfully achieved. The silver soldering had varied composition of Ag depending on the location. This shows uneven composition of the silver welding. A large quantities of S, that was not initially present, was detected on the surface of the black Odong. This indicates that presence of S has influence on Odong colour. Additional study on the chromaticity, additional chemical compounds and its restoration are needed for the further understanding of the origin of Odong colour. The result of Odong alloy testing and recreation, Odong silver inlay long sword production, scientific analysis of the Odong black colouring agent will form an important foundation of knowledge for conservation of Odong artifact.