• Journal of Welding and Joining
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• 제16권3호
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• pp.157-166
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• 1998

Recently as environmental pollution caused by Pb has posed a serious threat to the global environment, the trend to regulate the usage of Pb in electronic industry is one the rise. Currently, the solder alloy with high Pb content, Sn-37%Pb, is utilized in the electronic assembly therefore, the objective of this study is to develop an alternative solder alloy for the existing Sn-37%Pb solder alloy. First thing, this work choosed Sn-5%Pb-1.5%Ag, Sn-5%Pb-1.5%Ag-x%Bi(x=1~5%) for candidate solder alloys, and examined their properties such as melting range, wettability, microhardness, tensile property, oxidation behavior and microstructure. Wettability was on the same level of Sn-37%Pb. Dissolution of Pb ion in Sn-5%Pb solder was 0.46ppm. This solder alloy revealed cellular dendrite microstructure $\beta$-Sn matrix, Pb-rich phase, Ag/Sn, and Cu/Sn Intermetallic compounds. The range of solidification temperature was within 3$0^{\circ}C$. Also these alloy displayed higher tensile strength and lower elongation than Sn-37%Pb. The resistance of oxidation in Sn-5%Pb-1.5%Ag solder alloy was superior to that of Sn-37%Pb solder alloy. But that of Sn-5%Pb-1.5%Ag-5%Bi solder alloy was equal to that of Sn-37%Pb solder alloy.

• 한국표면공학회지
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• 제12권3호
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• pp.161-166
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• 1979

Theoretical and practical aspects are investigated for electrochemical behavious, plating processes and the structures of electrodeposit of Pb-Sn binary alloy plating through numerous literatures in this report. The anodic and cathodic electrode reaction mechanisms of Pb and Sn could co-deposit and make Pb-Sn alloy deposit from the results of cathode current density-cathode potential curves of Pb, Sn and Pb-Sn alloys in fluoborate solutions. The compositions of the best alloy plating solutions are obtained for the purpose of bearing, anticorrosion and solder plating. In general, the casting anodes of Pb-Sn alloys are used, but separated anodes of Pb and Sn pure metal are used in order to obtain the fine compositions of Pb-Sn alloy deposits. The electrodeposits of Pb-Sn alloy are in nonequilibrium state and saturated solid solutions. Thus, ${\beta}$-phase (Sn-phase) is precipitated by heat treatment. The texture and structure of the electrodeposit are associated with the surface energies of deposit lattice planes and with the cathode polarization. The electrodeposit of Pb-Sn alloy is shown as lamellar structure.

• 한국분말재료학회지
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• 제7권1호
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• pp.12-18
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• 2000

Effects of the microstrucrure of rapidy solidified Al-Pb-Cu-Mg alloys on the wear investigated. In order to overcome the miscility gap between Al and pb under equilibrium conditions, both in the solid and the liquid states, the alloy were rapidy solidifies to produce them in a segregation-free condition. Although the Pb particles showed relatively fine dispersion in the Al matrix in all the alloys by this process. the Al-16Pb alloy was found to have the most favorable microstructure with discretre with discrete Pb particles of abount 0.5 ${\mu}$m in size. With the addition of Cu and Cu-Mg to Al-16Pb, cellular structures were newly formed; not seen in the binary Al-Pb alloy. Wear properties of the Al-Pb binary alloys measured as a function of the sliding speen, sliding distance, and applied load showed that the Al-16Pb alloy has the best wear resistance, as expected from the fine microstructural features in this alloy. The were resistance of the alloy containing Cu-and Cu-Mg was higher than that of the Al-16Pvb alloy, due to matrix strengthening by precipitation hardeing. The wear mechanism was identified by examining the traces and wear debris.

• 한국재료학회지
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• 제8권11호
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• pp.1011-1019
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• 1998

Pb의 환경오염 문제를 발생하지 않는 저농도 Pb 솔도합금을 개발하기 위하여, 새로운 Sn-5%Pb-1.5%Ag-x%In계 합금 조성을 설계하고, 이 합금의 융점, 젖음성, 상분석, 경도, 인장강도, 드로스성을 평가하여, Sn-37%Pb 솔더오 대체 가능성을 타진하였다. Sn-37%Pb 솔도 합금의 Pbdldhs 용출농도는 국제규제치인 3ppm보다 훨씬 적은 0.46ppm이었고, 환경문제를 유발하지 않는 것으로 확인되었다. 이 합금계의 융점은 $183-192^{\circ}C$이고, 응고온도범위도 $5^{\circ}C$내외로 매우 좁았다. 젖음성은 In의 첨가양에 따라 큰 차이가 거의 없었으며, Sn-375Pb와 비슷하였다. 융점 및 젖음성 측면에서 Sn-37%Pb와 대체 가능한 것으로 판단되었다. 경도는 Sn-37%Pb의 약 1.5배이고, 인장강도는 Sn-37%Pb의 것보다 높고, In의 첨가량에 따라 증가하였지만, 연신율은 감소하였다. In이 1% 첨가된 합금에서는 수지 상정 경계에 Ag3Sn과 Pb가 정출되고, 3% 이상에서는 $Ag_3Sn$과 $Ag_3In$ 및 Pb가 정출되었다. 드로스 생성속도는 Sn-37%Pb 합금이 Sn-5%Pb-1.5%Ag 합금보다 빠르고, In을 첨가할수록 느리고 2%의 In을 첨가한 합금은 180분에서도 거의 드로스가 발생하지 않았다.

• Corrosion Science and Technology
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• 제3권4호
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• pp.131-139
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• 2004

Effects of PbO on the repassivation kinetics and characteristics of passive film of Alloy 690 were examined to elucidate the influences of PbO on the SCC resistance of that alloy. The repassivation kinetics of the alloy was analyzed in terms of the current density flowing from the scratch, i(t), as a function of the charge density that has flowed from the scratch, q(t). Repassivation on the scratched surface of the alloy occurred in two kinetically different processes; passive film initially nucleated and grew according to the place exchange model in which log i(t) is linearly proportional to q(t), and then grew according to the high field ion conduction model in which log i(t) is linearly proportional to 1/q(t) with a slope of cBV. The cBV is found to be a parameter representing repassivation rate and hence SCC susceptibility of the alloy. The lower the value of cBV, the faster the repassivation rate and the higher the SCC resistance of an alloy. Addition of PbO to pH 4 and 10 solutions increased the value of cBV of alloy 690, reflecting slower repassivation rate than without PbO. The change in the value of cBV was grater in pH 10 than in pH 4. The increase in SCC susceptibility of alloy 690 with the addition of PbO to solution was presumably due to the Cr-depletion in the outer parts of passive film of the alloy with an incorporation of Pb compounds in the film, which was revealed by Mott-Schottky, AES and XPS analyses.

• 한국표면공학회지
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• 제24권2호
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• pp.88-95
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• 1991

The tin-lead alloy was electrodeposited in the low range of peak current density in order to investigate the change of composition and microstructure of them. The Pb content of alloy deposits, which was decreased with increasing average current density, was relatively lower than that of D.C. plated alloy deposit. The preferred orientation of alloy deposit was changed with increasing peak current density and the surface morphology of alloy deposits was closely related to the preferred orientation of them.

• 한국표면공학회지
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• 제22권4호
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• pp.207-214
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• 1989

The surface morphology and the proferred orientation of the Pb-Sn alloy electrodeposite were investated by the change of electrolysis conditions in pulse current electroplating. The preferred orientation of Pb-phase in alloy deposits was changed in the sequence of (110)longrightarrow(100)or(100)+(111)longrightarrow(111) with increasing peak current density, while that of $\beta$-Sn phase changed from (321)+(301)to(301)+(111) mixed orientation. The surface morphology was closely related to the preferred orientation of alloy electrodeposits. The alloy deposits, which had (100)or(111) for pb-phase and (321)or(100)(301)for $\beta$-Sn sespectively, showed the surface structure of granular crystallites. The alloy deposits whih mixed orientations for both phases had microstructure of closely the closely stacked crysrallites, which was inclined to the surface.

• 자원리싸이클링
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• 제21권4호
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• pp.53-59
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• 2012

본 연구에서는 비철제련의 공정 부산물에서 얻어진 Bi-Pb-Sb 3원계 합금 용탕의 산화반응에 따른 Sb과 Pb의 제거거동에 대하여 조사하였다. $N_2+O_2$ 가스를 침지 노즐을 통해 1173 K의 합금 용탕 중에 취입하여 Sb을 산화물과 금속상의 혼합물로 분리 회수할 수 있었다. 그리고 923 K의 Bi-Pb 2원계 용탕에 $N_2+O_2$ 가스를 취입하면 Pb가 산화되어 슬래그상으로 제거될 수 있으나, Bi도 동시에 산화되어 Bi를 정제할 수 없었다.

• 한국주조공학회지
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• 제10권5호
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• pp.392-398
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• 1990

To improve free-cutting property, fine Pb, Bi particles is necessary to be distributed evenly in Al-Cu alloy. The control of added element size and distribution are very difficult because of the physical properties of Pb, Bi. The effect of master alloy compositions on microstructure and particle distribution was investigated. The ribbon shape of Pb-50wt% Bi master alloy showed the best results. And Ti addition improved even distribution of Pb, Bi particles. Particles grown from $L_2$ phase were considered to be the Pb, Bi compound.

• 한국표면공학회지
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• 제22권4호
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• pp.197-206
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• 1989

The Composition and throwing power-of Pb-Sn alloy deposits are investigated in tems of the pulse parameters in pulse plating. Microhardness and intermal srress of alloy deposots are measured. The current efficiency of pulse plating is lower than that of D.C.plating while cathode overpotential and macro-throwing power noticebly increase with increasing peak current density. The Pb content of P.C. plated alloy deposits with increasing average current density, is relatively lower than of D.C. plated deposits at the same average current density. The internal stress of Pb-Sn alloy is not detected and the microhardness are 9.0kg/mm2 and 11kg/mm2 for D.C. plated P.C. plated deposits, respectively.