• 한국전기전자재료학회논문지
• /
• 제20권6호
• /
• pp.561-565
• /
• 2007

Because of a good wear resistance and a stable contact resistance, Ag-CdO is widely used as electrical contact material. But, the Cd-oxide mainly exists as a coarse particle and adversely affected to environment. As a reason, $Ag-SnO_2$ alloy has been developed. The Sn-oxide maintains stable and fine particle even at high temperature. In order to investigate the effect of Misch metal (Mm) additional that affects the formation of the oxide and the formation of fine matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Mm) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. The Mm addition makes Ag matrix more fine than no Mm addition. The reason is that the addition of Misch metal decreased a latent heat of fusion of alloy, as a result the rapid solidification effect of alloy is increased. The maximum hardness shows at 0.3 wt%Mm. after that the hardness is decreased until 0.4 wt% Mm, but still larger than no Mm addition alloy. At 0.5 wt% Mm alloy, the precipitation of Misch metal causes a decrease of hardness than no Mm addition alloy.

• 한국표면공학회지
• /
• 제57권3호
• /
• pp.192-200
• /
• 2024

Cu as a heat exchanger tube is an important component in thermal fluid transfer. However, Cu tubes are exposed to stress in certain environments, leading to stress corrosion cracking (SCC). In this study, the effect of Sn addition on microstructure and corrosion characteristics was examined. The microstructural examination revealed the presence of columnar crystal and a grain refinement due to the addition of Sn. Electrochemical measurements showed that the 5 wt.% NH₃ environment was the most vulnerable environment to Cu corrosion, and the corrosion current density increased as stress increased. The immersion test exhibited the formation of Cu2O and Cu(OH)₂ corrosion product in 3.5 wt.% NaCl and 5 wt.% NH₃ environments, respectively. Results indicated that Sn addition to Cu was an important factor in improving the mechanical strength.

• Journal of Welding and Joining
• /
• 제16권3호
• /
• pp.148-156
• /
• 1998

The purpose of this study is to investigate the characteristics of Pb-Free Sn-2%Ag-Bi solder alloys. The solder alloys used in this study is Sn-2%Ag-(3,5,7,9%) Bi It is examined that their properties such as melting range, wettability, microstructure, microhardness, and tensile property. The addition of Bi(3,5,7,9%) lowered the melting point of the solder and the melting range was 196~203$^{\circ}C$. The wettability of the solder as equal to that of Sn-37% Pb solder. The morphology of structure did not change largely by addition of Bi. But the structure of cellular dendrite of linear type displayed. The tensile strength of the solder was superior to that of Sn-37%Pb solder. But the elongation was inferior to that of Sn-37%Pb solder. The hardness of Sn-2%Ag solder was tow times and that of Sn-2%Ag-Bi solder was three times of that in Sn-37%Pb solder. But the effect of increment of Bi content did not change largely.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.104-107
• /
• 2001

In order to investigate the effect of Ge addition to the Cu matrix on the microstructure and the critical current density, four kinds of internal tin processed Nb$_3$Sn strands with pure Cu and Cu 0.2, 0.4, 0.6 wt % Ge alloys were drawn to 0.8 mm diameter. The microstructure and critical current of internal tin processed Nb$_3$Sn wires that were heat treated at temperatures ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$ for 240h were investigated. The Ge addition to the matrix did not make workability worse. A Ge rich layer in the Cu-Ge matrix suppressed the growth of the Nb$_3$Sn layer and promoted grain coarsening. The greater the Ge content in the matrix, the lower the net Jc result after Nb$_3$sn reaction heat treatment. There was no significant variation in Jc observed with heat treatment temperature ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$. The values of AC loss of Ge added wires were decreased to 40 % compare with no addition wire. Low AC loss was due to segregation of Ge rich layer in the Cu-Ge matrix. If Ge added wire with thin Nb filaments were fabricated, slow diffusion rate of Sn would be overcome and decreased AC loss that is weak Point of internal tin method.

• 한국재료학회지
• /
• 제26권7호
• /
• pp.376-381
• /
• 2016

For the development of a low-melting point filler metal for brazing aluminum alloy, we analyzed change of melting point and wettability with addition of Sn into Al-20Cu-10Si filler metal. DSC results showed that the addition of 5 wt% Sn into the Al-20Cu-10Si filler metal caused its liquidus temperature to decrease by about 30 oC. In the wettability test, spread area of melted Al-Cu-Si-Sn alloy is increased through the addition of Sn from 1 to 5 wt%. For the measuring of the mechanical properties of the joint region, Al 3003 plate is brazed by Al-20Cu-10Si-5Sn filler metal and the mechanical property is measured by tensile test. The results showed that the tensile strength of the joint region is higher than the tensile strength of Al 3003. Thus, failure occurred in the Al 3003 plate.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1989년도 춘계학술대회 논문집
• /
• pp.52-55
• /
• 1989

The properties of sintered Ag-SnO$_2$contacts which contain the second oxide were investigated with hardeness, workability, electrical conductivity and are erosion. Ag-SnO$_2$contacts containing ZnO or Bi$_2$O$_3$have most excellent workability and arc erosion endurance.

• 한국분말재료학회지
• /
• 제29권5호
• /
• pp.357-362
• /
• 2022

The low-temperature sinterability of TiO₂-CuO systems was investigated using a solid solution of SnO₂. Sample powders were prepared through conventional ball milling of mixed raw powders. With the SnO₂ content, the compositions of the samples were Ti_1-xSn_xO₂-CuO(2 wt.%) in the range of x ≤ 0.08. Compared with the samples without SnO₂ addition, the densification was enhanced when the samples were sintered at 900℃. The dominant mass transport mechanism seemed to be grain-boundary diffusion during heat treatment at 900℃, where active grain-boundary diffusion was responsible for the improved densification. The rapid grain growth featured by activated sintering was also obstructed with the addition of SnO₂. This suggested that both CuO as an activator and SnO₂ dopant synergistically reduced the sintering temperature of TiO₂.

• 한국재료학회지
• /
• 제11권2호
• /
• pp.104-114
• /
• 2001

Zr-Sn-Nb 합금의 재결정에 미치는 Nb과 Sn의 첨가영향을 연구하기 위해 냉간압연한 시편을 $300^{\circ}C$~75$0^{\circ}C$의 온도구간에서 열처리한 후에 미소경도와 TEP (Thermoelectric Power)를 측정하여 재결정 거동을 조사하였으며 광학현미경, 주사전자 현미경 (SEM), 투과전자현미경 (TEM)으로 미세조직을 관찰하였다 미소경도 및 미세조직의 분석 결과에 따르면, Nb과 Sn의 첨가에 의해 재결정 활성화 에너지가 증가하여 재결정이 지연되었으며, 재결정 완료 이후의 결정립 성장도 억제되었음을 관찰하였다. Zr내의 고용도가 매우 낮은 Nb의 첨가는 석출물을 쉽게 형성하는 반면에 고용도가 비교적 큰 Sn은 기지상 내에 대부분 고용되어 석출물의 양이 매우 작았으나, Sn 첨가에 의한 재결정의 지연 효과가 더욱 컸다. Nb보다 Sn의 첨가가 Zr 합금의 재결정 거동을 효과적으로 지연시킨 것은 고용도가 높은 SR에 의한 치환형 고용체 형성과정에서 발생된 응력장이 전위의 이동을 효과적으로 억제했기 때문으로 생각된다. 한편, 회복과 재결정이 진행됨에 따라 전자 산란인자의 감소로 TEP는 증가하였으며, 재결정이 완료되면 TEP의 포화가 발생하였다. 석출물의 형성은 석출물 주변의 용질농도 감소로 인한 전자 산란인자의 감소에 기인하여 TEP의 증가를 가져왔다

• 열처리공학회지
• /
• 제28권5호
• /
• pp.229-238
• /
• 2015

The effects of Sn addition and solution treatment on corrosion behavior were studied in AZ91 magnesium casting alloy. The addition of 5%Sn contributed to the introduction of $Mg_2Sn$ phase, to the reduction in dendritic cell size and to the increase in the amount of secondary phases. After the solution treatment, trace amount of $Al_8Mn_5$ particles were observed in the ${\alpha}$-(Mg) matrix for the AZ91 alloy, while $Mg_2Sn$ phase with high thermal stability was additionally found in the AZ91-5%Sn alloy. Before the solution treatment, the AZ91-5%Sn alloy had better corrosion resistance than the Sn-free alloy, which is caused by the enhanced barrier effect of the (${\beta}+Mg_2Sn$) phases formed more continuously along the dendritic cell boundaries. It is interesting to note that after the solution treatment, the corrosion rate of both alloys became increased, but the Sn-added alloy showed higher corrosion rate than the Sn-free alloy. The microstructural examination on the corroded surfaces revealed that the remaining $Mg_2Sn$ particles in the solution-treated AZ91-5%Sn alloy play a role in accelerating corrosion by galvanic coupling with the ${\alpha}$-(Mg) matrix.

• 마이크로전자및패키징학회지
• /
• 제20권3호
• /
• pp.53-57
• /
• 2013

Sn-3.0Ag-0.5Cu 무연솔더에서 Ag 함량의 감소는 기계적 충격 신뢰성 향상에 도움이 되는 반면 솔더링성을 저하시키는 것으로 알려져 있다. 본 연구에서는 저 Ag함유 무연솔더의 솔더링성 향상을 위해 In을 첨가한 Sn-1.2Ag-0.7Cu-0.4In 4원계 조성과 여기에 미량의 Mn 및 Pd을 첨가한 무연솔더 조성에 대하여 솔더 젖음성을 평가하고, 보드 레벨 BGA 패키지의 열싸이클링 및 기계적 충격 신뢰성을 평가하였다. Sn-1.2Ag-0.7Cu 조성에 0.4 wt% In을 첨가한 합금의 젖음성은 Sn-3.0Ag-0.5Cu에 근접한 수준으로 향상되었으나, 패키지의 열싸이클링 신뢰성은 Sn-3.0Ag-0.5Cu에 미치지 못하는 것으로 나타났다. Sn-1.2Ag-0.7Cu-0.4In 조성에 0.03 wt% Pd의 첨가는 솔더 젖음성 및 패키지 신뢰성을 저하시킨 반면에 0.1 wt% Mn을 첨가한 합금은 특히 기계적 충격 신뢰성이 Sn-3.0Ag-0.5Cu는 물론 Sn-1.0Ag-0.5Cu보다도 우수한 수준으로 향상되었는데, 이는 Mn 첨가가 합금의 모듈러스를 감소시킨 데에 기인하는 것으로 생각된다.