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Microstructure and Mechanical Characteristics of the Ternary SnZnAl Lead-Free Alloy

Pietrzak K., Klasik A., Maj M., Sobczak N.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

31--36

EN

The paper describes the studies of ternary SnZn9Al1.5 lead-free alloy from the viewpoint of its mechanical behavior as well as microstructure examined by the light and scanning electron microscopy. The authors focused their attention specifically on the fatigue parameters determined by the original modified low-cycle fatigue method (MLCF), which in a quick and economically justified way allows determination of a number of mechanical parameters based on the measurement data coming from one test sample only. The effect of the addition of 1.5% Al to the binary eutectic SnZn9 alloy on its microstructure and the obtained level of mechanical parameters was analyzed. The phases and intermetallic compounds occurring in the alloy were identified based on the chemical analysis carried out in micro-areas by the SEM/EDS technique. It was shown that the addition of 1.5% Al to the binary eutectic SnZn9 alloy resulted in a more favorable microstructure and consequently had a positive effect on the mechanical parameters of the alloy. Based on the conducted research, it was recommended to use a combinatorial method based on the phase quanta theory to quickly evaluate the microstructure and the original MLCF method to determine a number of mechanical parameters.

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Microstructure and Fatigue Life of the Binary Lead-free Alloys with High Zn Content

Pietrzak K., Klasik A., Maj M., Sobczak N.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

65--70

EN

The results of studies presented in this article are an example of the research activity of the authors related to lead-free alloys. The studies covered binary SnZn90 and SnZn95 lead-free alloys, including their microstructure and complex mechanical characteristics. The microstructure was examined by both light microscopy (LM) and scanning electron microscopy (SEM). The identification of alloy chemical composition in micro-areas was performed by SEM/EDS method. As regards light microscopy, the assessment was of both qualitative and quantitative character. The determination of the geometrical parameters of microstructure was based on an original combinatorial method using phase quantum theory. Comprehensive characterization of mechanical behavior with a focus on fatigue life of alloys was performed by means of the original modified low cycle fatigue method (MLCF) adapted to the actually available test machine. The article discusses the fatigue life of binary SnZn90 and SnZn95 alloys in terms of their microstructure. Additionally, the benefits resulting from the use of the combinatorial method in microstructure examinations and MLCF test in the quick estimation of several mechanical parameters have been underlined.

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Wpływ rodzaju pokrycia oraz stosowanego topnika na lutowność płytek PCB stopem SAC305

Siewiorek A., Kudyba A., Homa M, Sobczak N.

Prace Instytutu Odlewnictwa

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2012

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T. 52, z. 3

77-91

PL

W pracy przedstawiono wyniki badań wpływu rodzaju pokrycia oraz topnika na lutowność płytek PCB bezołowiowym stopem o osnowie cyny SAC305 (SnAg3,0Cu0,5) poprzez pomiar siły Fr i czasu zwilżania t0 metodą meniskograficzną oraz wyznaczanie wielkości kąta zwilżania θ. Badania wykonano w temperaturze 260°C na płytkach z trzema rodzajami pokrycia (HASL LF - bezołowiowe, ENIG - złote, OSP - organiczne), stosując 2 gatunki topnika (EF2202 i RF800). Najkrótszy czas zwilżania t0 = 0,6 s dla topnika EF2202 i t0 = 0,98 s dla topnika RF800 zanotowano w przypadku płytek z pokryciem OSP. Dla płytek z pokryciem ENIG czas zwilżania t0 = 1,36 s (topnik EF2202) i t0 = 1,55 s (topnik RF800) był najdłuższy. Obliczona wielkość kąta zwilżania θ wyniosła: dla płytek PCB z pokryciem HASL LF - θ = 45°, z pokryciem ENIG - θ = 58°, a z pokryciem OSP - θ = 63°.

EN

This paper presents the results of tests on the effect of the surface coating and flux type on the solderability of PCB by lead-free tin-based SAC305 (SnAg3.0Cu0.5) alloy determining the size of the contact angle by a wetting balance method. The study was performed at a temperature of 260°C on PCB with three types of coatings (HASL LF - lead-free, ENIG - gold, OSP - organic coating), using two types of flux (EF2202 and RF800). The shortest wetting time t0 = 0.6 s for the EF2202 flux and t0 = 0.98 s for the RF800 flux was obtained for plates with the OSP coating. For ENIG-coated PCB, the wetting time t0 = 1.36 s (EF2202 flux) and t0 = 1.55 s (RF800 flux) was the longest. The calculated angle θ was as follows: for PCB with HASL LF - θ = 45°, with ENIG - θ = 58°, and for the OSP coating - θ = 63°.

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Badanie zwilżalności podłoży miedzianych bezołowiowymi stopami lutowniczymi

Bukat K., Gromek J., Moser Z.

Przegląd Spawalnictwa

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2007

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R. 79, nr 9

130-134

PL

W związku z wprowadzeniem Dyrektywy RoHS 1.07.2006 roku, do lutowania w elektronice stosowane są stopy bezołowiowe. Charakteryzują się wyższymi temperaturami topnienia i wyższymi napięciami powierzchniowymi od tradycyjnego stopu SnPb. Nie ustają poszukiwania zamienników stopu SnPb. Przedmiotem badań było napięcie powierzchniowe i międzyfazowe stopów bezołowiowych SnAgCu, SnAgCuBi, SnZn, SnAgZn oraz zwilżanie podłoży miedzianych tymi stopami. Stwierdzono, że dodatek bizmutu do stopu SnAgCu powoduje spadek napięcia powierzchniowego i międzyfazowego w stosunku do stopu trójskładnikowego. Otrzymany stop SnAgCuBi dobrze zwilża podłoże miedziane. Eutektyczny stop SnZn wykazuje wyższe napięcie powierzchniowe niż stop SnPb. Zwiększanie zawartości cynku w eutektyce Sn3,5Ag powoduj wzrost napięcia powierzchniowego i międzyfazowego oraz brak poprawy zwilżania powierzchni miedzianych.

EN

Directive RoHS came into practice from 1st July 2006 and forced using lead-free solders for soldering in electronics. These new solders have higher melting temperature and higher surface tension than SnPb. Investigition of new lead-free solder persists in doing. The subject of studies were surface tension, interfacial tension of the SnAgCu, SnAgCuBi, SnZn, SnAgZn lead-free solders as well as copper wettability by these solders. It was established that the SnAgCu solder with different addition of Bi demonstrates decrease of the surface tension and interfacial tension in comparison to ternary solder. Obtained SnAgCuBi solder wets very well copper substrate. Eutectic SnZn alloy has a higher surface tension than SnPb. Increasing amount of Zn element in Sn3,5Ag alloy demonstrates increase surface and interfacial tensions without improving wettability of copper surfaces.