Papers by Keyword: Solder

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Authors: Georgiana Melcioiu, Viorel Aurel Şerban, Mark Ashworth, Cosmin Codrean, Marin Liţă, Geoffrey D. Wilcox
Abstract: Components soldered with Sn-based alloys are susceptible to the growth of whiskers. Tin whiskers have been proven to be responsible for equipment failures in a wide range of industries. In order to reduce defects in electronic components a new solder alloy is proposed based on the Sn-Cu alloys. The Sn-Cu-Ga alloy utilised in this study was fabricated as a ribbons using melt-spinning method. These ribbons were then soldered onto electroplated tin layers. Preliminary characterization of the solder alloy is presented in this paper, including scanning electron microscopy, EDX mapping and X-ray diffraction. Key words: tin whiskers, PCB, printed circuit boards, melt spinning, solder, ribbons
Authors: Sylwia Wiewiórowska, Zbigniew Muskalski, Maciej Suliga
Abstract: The variety of industrial use of brazing solders is associated in one way with plastic properties (more plastic materials are producing in the form of wires, sheets, bands, metal leafs, meshes etc, low plastic materials in the form: pig sows, bars, powders) and in another way with the kind of joining and use soldering or brazing method. Hard solders, which include analyzed solder BAg7, have a very wide range of melting points (from 400 to 2000°C) and are applied in those cases when very high values of strength are required for soldered joint. The research was carried out for the silver-based solder designated as Bag7 according to American Standard ANSI/AWSA 5.8-92. This solder has a typical application for the brazing process of food handling equipment requiring low melting values and for brazing aluminium alloys. In the literature, except for chemical composition and temperature of brazing, we cannot find the details concerned with the method of plastic working of BAg7. In the reported research work the metallographic analysis of rolling process was performed and optimal parameters of rolling process for the considered solder were determined.
Authors: Ikuo Shohji, Tatsuya Kobayashi, Tomotake Tohei
Abstract: The aim of this study is to investigate the relationship between the inelastic strain range and the thermal fatigue lives of chip size package solder joints with Sn-Pb and Sn-Ag-Cu solder balls. The inelastic strain range was examined by finite element analysis. In both solder joints, the exponential terms in the inelastic strain range term in the Coffin-Manson equation were evaluated as 1.8 - 2.3. These values are very close to the conventional one used in Sn-Pb and the Pb containing solders. The inelastic strain range is almost proportional to the temperature range in the Sn-Pb solder joint. On the contrary, the inelastic strain range is proportional to approximately the square root of the temperature range in the Sn-Ag-Cu solder joint. The deference depends on the change of the stress-strain hysteresis curve in the thermal cycle.
Authors: Miroslav Jáňa, Milan Turňa, Milan Marônek, Marcel Kuruc, Pavel Bílek
Abstract: Contribution deals with soldering of Mg alloy AZ31B by ternary solder ZnAl6Ag6 with ultrasonic support. Suggested solder has been analyzed from many aspects. Microstructure of solder consistutes of solid solution α-Al (FCC_Al), β-Zn (HCP_Zn) and intermetallic phases AgZn3 and AlAg3. Melting temperature of solder 386.8 °C has been determined by DSC analysis. Metallurgical process of ultrasonic soldering has run at 410 °C for 3 s. Soldered joint has been constituted by eutectic ternary structure β-Mg17(ZnAl)12, solid solution α - Mg, which contains Al and Ag elements. At solder-substrate interface, there has been formed intermetallic phase Mg2Zn11. The highest value of microhardness has been 260 HV. To predict lifetime of soldered joint, calculations in software Thermo-Calc has been performed.
Authors: S. Amares, Mohd Noor Ervina Efzan, T.C. Yap
Abstract: As the electronic packaging industry is vastly being developed, the solder plays a crucial role in providing integrity electronic assemblies. Unfortunately, the traditional Sn-Pb solder is harmful to the environment and human due to lead (Pb) it contains. Hence, in this study, the Sn-Bi lead free solder alloy is investigated based on its physical properties together with melting temperature, hardness and microstructure. Investigation shows that this solder provides a low melting temperature of, Tm=141.08°C which is lower than the most used Sn-Pb, Tm=183°C and Sn-Ag-Cu, Tm=227°C. Moreover, the Sn-Bi solder also produces well-defined microstructures with Sn-matrix and bismuth precipitation on the matrix. The Sn-Bi solder also provides a higher hardness with average of 11.8Hv for Vickers hardness and 3.87BHN for Brinell hardness. All this results seem to satisfies the environment as well as producing better physical properties.
Authors: Satoshi Tanimoto, Kohei Matsui, Yusuke Zushi, Shinji Sato, Yoshinori Murakami, Masato Takamori, Takashi Iseki
Abstract: A new high-temperature die attachment system that is cost effective has been strongly desired for SiC power applications in electric vehicles and consumer electronics. This paper presents preliminary results for SiC/Zn-Al/Cu-SiN die attachments using eutectic Zn-Al solder (m.p. = 356°C), focusing on preparation and die-shear reliability. Superior wettability and reproducibility were achieved in the soldering process. It was found that the attachments were viable at least for short-term application in a temperature range up to 300°C. Reliability test results revealed that they could withstand storage for 1500 hours at 200°C and thermal cycle stress of 1500 cycles between –40°C and 200°C.
Authors: Piyarach Eutrirak, Viritpon Srimaneepong, Kanokwan Saengkiettiyut
Abstract: This paper investigates the quality and corrosion property of Ni-free Co-Cr alloy joints soldered and laser welded using filler. The soldered and laser-welded test specimens were sectioned at the center and rejoined by either soldering or laser welding using appropriate fillers. The joint area was analyzed using microfocus X-ray and the percentage of porosity, as a measure of joint quality, was calculated. The corrosion behavior of soldered and laser-welded test specimens was evaluated using a potentiodynamic polarization technique in a 0.9 wt.% NaCl solution, pH 2.3, at 37°C. The results indicated that the amount of porosity and cracks in soldered joints were less than those of the laser-welded joints, leading to a lower corrosion rate.
Authors: M.N. Ervina Efzan, R. Kamaneeya
Abstract: The corrosion of Sn-Zn-Bi lead free solder in 6M KOH electrolyte was conducted. The study was done using 3 different KOH concentrations (3M, 6M and 9M) and the immersion technique was used to produce corrosion. Due to the nature of immersion, the solder material was prepared by punching it into small billets size after melting it homogenously on a commercial hotplate. The immersion was set to 7, 14 and 21 days. After the specific days have fulfilled the sample billets were removed and tested. The corrosion of this solder was measured using various method such as graphical analysis, surface roughness, corrosion penetration rate (CPR) and optical microscope. In this research, it was found out that the sample billets taken from 6M concentration compared to 3M and 9M showed more corrosion this was supported by the outcome of the test. The 6M believed to provide best corrosion on the solder billets because of its high ionic conductivity value.
Authors: Zarrul Azwan Mohd Rasid, Mohd Hafiz Zainol, Mohd Firdaus Omar, Mohd Nazree B. Derman, Muhammad Firdaus Mohd Nazeri
Abstract: Corrosion properties of Sn-9Zn and Sn-0.7Cu solder were investigated in 3.5 wt.% NaCl. The scanning rates used were fixed at 1.0mVs-1 to study the effect of diffferent adding element which is Cu and Zn into the corrrosion properties of Sn-based solder. The morphological and structural properties of the samples were compared before and after the corrosion. The morphological analysis observed two types of corrosion product which is compacted and loosely-compacted corrosion product after the samples was polarized in 3.5% NaCl solution.
Authors: Nordarina Jumali, Ahmad Azmin Mohamad, Muhammad Firdaus Mohd Nazeri
Abstract: The corrosion properties of Sn-9Zn lead-free solder was studied through potentiodynamic polarization in different concentration of hydrochloric acid (0.5, 1.0, 1.5, 2.0 M). Two types of polarization profile were observed for Sn-9Zn solder at lower concentration acid (0.5 to 1.0 M) and one at higher concentration acids (1.5 to 2.0 M). The morphological analysis showed that two distinctive structures of lamellar-like groove and irregular shaped of the corrosion product compounds formed on the solder surface after being polarized at different concentrations. Phase and elemental analyses revealed the formation of mixed corrosion product such as SnO, SnO2, ZnO, ZnO2, and Zn(OH)2 on the surface after polarization.
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