• Title/Summary/Keyword: Partial Melting Process

Search Result 51, Processing Time 0.023 seconds

POSSIBILITY OF PARTIAL MELTING SOLDERING PROCESS WITH OFF EUTECTIC LEAD FREE SOLDER ALLOYS

  • Kang, Choon-Sik;Ha, Jun-Seok;Park, Jae-Yong;Jung, Jae-Pil
    • Proceedings of the KWS Conference
    • /
    • 2002.10a
    • /
    • pp.791-797
    • /
    • 2002
  • This paper introduces the partial melting process for solder application and characterization of its feasibility using Sn-Ag, and Sn-Cu solder alloys. ill order to show that the liquid phase in the semi-liquid state maintains the similar wettability as single-phase liquid, the wetting balance tests are conducted with varying temperatures and compositions. Also, as a new soldering technology, the microstructural and mechanical test were investigated. The results from this research indicate that the partial melting can yield satisfactory sider joints as long as the liquid phase acquires sufficient chemical activity. At a condition where the partial melting is effective, a direct correlation between the wettability and the surface tension is found to exist.

  • PDF

Zone-melting Process of NdBaCuO under Low Oxygen Pressure

  • Soh, Dea-Wha
    • Transactions on Electrical and Electronic Materials
    • /
    • v.3 no.2
    • /
    • pp.24-27
    • /
    • 2002
  • The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1%O$_2$+99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ film 1,06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCuO$_2$ and CuO) was reduced during: the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted Nd$_{1+x}$Ba$_{2-x}$Cu$_3$O$_{y}$ prepared under low oxygen partial pressure was distinctively improved.d.d.d.

Cr-Co removable partial denture treatment fabricated by selective laser melting: a case report (Selective Laser Melting을 이용한 코발트-크롬 가철성 국소의치의 수복 증례)

  • Yim, Ji-Hun;Shin, Soo-Yeon
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.37 no.1
    • /
    • pp.39-47
    • /
    • 2021
  • Compared to conventional method, if metal framework of removable partial denture is fabricated by selective laser melting, various laboratory works are omitted, saving time and simplifying the process. In addition, metal framework with homogeneous density can be obtained, expecting excellent mechanical properties, especially resistance to fatigue fracture. In these cases, impression were taken using conventional methods in partial edentulous patients, master casts were fabricated and scanned to obtain digital data. After designing the metal frameworks on the scanned data, removable partial dentures were fabricated using selective laser melting methods. Through these procedure, satisfactory outcomes were achieved both in functional and esthetic aspects.

Study on the Soldering of Off-eutectic Pb-Sn Solders in Partial Melting State

  • Park, Jae-Yong;Ha, Jun-Seok;Kang, Choon-Sik;Shin, Kyu-Sik;Kim, Moon-Il;Jung, Jae-Pil
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.7 no.2
    • /
    • pp.63-68
    • /
    • 2000
  • This paper introduces the partial melting process for solder application and characterization of its possibility using off-eutectic Pb-Sn alloy. In order to show that the liquid phase in the semi-liquid state maintains the wettability as the single-phase liquid, the wetting balance test are conducted with varying temperatures and compositions. The results are then compared with the surface tension of liquid, both measured and calculated, to examine the correlation. The results from this investigation indicate that the partial melting can yield satisfactory solder joints as long as the liquid phase acquires sufficient chemical activity. At a condition where the partial melting is effective, a direct correlation between the wettability and the surface tension is found to exist. All alloys are found to show a reasonable wettability in semi-liquid state.

  • PDF

Fabrication of BSCCO Superconductor Tube for Current Lead Application (전류인입선 응용을 위한 BSCCO 초전도 튜브의 제조)

  • Choi, Jung-Suk;Jun, Byung-Hyuk;Hyun, Ok-Bae;Kim, Chan-Joong
    • Progress in Superconductivity
    • /
    • v.10 no.2
    • /
    • pp.103-107
    • /
    • 2009
  • $Bi_2Sr_2Ca_1Cu_2O_x$(BSCCO 2212) superconductors for current lead were fabricated by centrifugal melting process(CMP). BSCCO 2212 powder was melted at $1200^{\circ}\C$ in a resistance furnace using a Pt crucible and poured in a rotating cylindrical mold preheated at $550^{\circ}\C$ for 2 hour. The solidified BSCCO-2212 samples were heat-treated by partial melting process in oxygen atmosphere. The current-voltage curves at 77 K of the samples were obtained by transport measurement, and the microstructure was investigated by scanning electron microscope. The $J_c$ values at 77 K of the tubes partially melted at $840^{\circ}C,\;860^{\circ}C\;and\;880^{\circ}C$ were 492, 430 and 398 $A/cm^2$, respectively. It was observed that the plate-like grains in BSCCO 2212 tube was more developed in the sample heat-treated at $840^{\circ}C$. It was found that the critical current of the BSCCO 2212 samples was dependent on the partial melting schedule regarding the grain shape and size of the BSCCO 2212.

  • PDF

Characteristics of Bi-2212 Superconductor Tube Depending on Heat-treatment Conditions (열처리 조건에 따른 Bi-2212 초전도 튜브의 특성)

  • 박용민;장건익
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.7
    • /
    • pp.606-610
    • /
    • 2001
  • Bi-2212 HTS tube was fabricated by centrifugal forming and partial melting processes. Bi-2212 bulk tube has been optimized to achieve smooth surface and uniform thickness. The slurry was prepared in the mixing ratio of 10:1 between Bi-2212 powder and binder and initially charged into the rotating mold under the speed of 300~450 rpm. Heat-treatment was performed at the temperature ranges of 860~89$0^{\circ}C$ in air for partial melting. the HTS tube fabricated by centrifugal forming process at 89$0^{\circ}C$ under the rotating speed of 450 rpm was highly densified and the plate-like grains with more than 20${\mu}{\textrm}{m}$ were well oriented along the rotating axis. The measured Tc and J$_{c}$ at 10K on specimen heat treated at 89$0^{\circ}C$ was around 85 K and 1,200 A/$\textrm{cm}^2$ respectively.y.

  • PDF

Zone-melting Process of NdBaCuO Superconductor under Low Oxygen Pressure

  • Soh, Deawha;Zhanguo, Fan;Yingmei, Li
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2004.05a
    • /
    • pp.6-8
    • /
    • 2004
  • The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1 % $O_2$+99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ from 1, 06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCu $O_2$and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted N $d_{1+x}$B $a_{2-x}$C $u_3$ $O_{y}$prepared under low oxygen partial pressure was distinctively improved.d.d.d.

  • PDF

Preparation of Zone-melted NdBaCuO under Low Oxygen Pressure

  • Soh, Dea-Wha;Fan, Zhan-Guo;Gao, Wei-Ying;Jeon, Jong-Woo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.11b
    • /
    • pp.85-88
    • /
    • 2001
  • The NdBaCuO superconductor samples were Zone-melted in low oxygen partial pressure (1% $O_{2}+ 99% Ar$ ). The Zone-melting temperature was decreased about $120^{\circ}C$ from $1060^{\circ}C$ the zone-melting temperature in air. Thus the loss of liquid phase ($BaCuO_{2}$ and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased, so was the substitution of Nd for Ba. The superconductivity of zone-melted $Nd_{1+x}Ba_{2-x}Cu_{3}O_{y}$ prepared under low oxygen partial pressure was distinctively improved.

  • PDF

Preparation of Zone-melted NdBaCuO under Low Oxygen Pressure

  • wha, Soh-Dea;guo, Fan-Zhan;ying, Gao-Wei;Jeon Yongwoo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.11a
    • /
    • pp.85-88
    • /
    • 2001
  • The NdBaCuO superconductor samples were Zone-melted in low oxygen partial pressure (1% O$_2$+99% Ar). The Zone-melting temperature was decreased about 120$^{\circ}C$ from 1060$^{\circ}C$ the zone-melting temperature in air. Thus the loss of liquid phase (BaCuO$_2$ and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased, so was the substitution of Nd for Ba. The superconductivity of zone-melted Nd$\sub$1+x/Ba$\sub$2-x/Cu$_3$O$\sub$y/ prepared under low oxygen partial pressure was distinctively improved.

  • PDF