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21 (06.4.3) |
Evaluating hot-dipped solder plating with corrosion testing |
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Abstract
To evaluate solder plating materials for corrosion resistance, we coated copper materials with several types of hot-dipped solder plating, and then we performed the following tests on these specimens: the salt mist cyclic test, the gas corrosion test, and the weathering test. Following these tests, we analyzed both surfaces and cross sections to investigate the causes of corrosion of the solder plating materials and the effects of corrosion on the copper substrate. |
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19 (05.4.1) |
Evaluating joint reliability of Sn-Zn low-temperature, lead-free
solder |
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Abstract
The commercial adoption of lead-free solder materials in electronic parts and
part assembly is now well under way. However, the melting point of lead-free
solder is considerably higher than that of conventional solder with lead,
and so there is some concern about the effect of these higher temperatures
on the parts during assembly. Among the lead-free solder materials, Sn-Zn
solder is known to have a low melting point, and is starting to gain acceptance.
To encourage further acceptance of Sn-Zn solder, studies must be carried out
evaluating the reliability of this solder material.
Consequently, we have prepared this report evaluating various reliability factors
of Sn-8Zn-3Bi lead-free solder. |
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17 (04.4.1) |
Promoting the commercial adoption of lead-free solder and evaluating
its reliability |
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Abstract
This report will present the details of our efforts to promote the adoption
of commercially viable PCBs using lead-free solder as well as the results
of our reliability test evaluations of PCBs in mass produced products. |
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15 (03.4.1)
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Factors affecting reliability of Sn-Ag-Cu solder |
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Abstract
Reliability of Sn-Ag-Cu solder joint strength is evaluated using temperature
cycle tests and high-temperature tests. This report analyzes the performance
of Sn-3.5Ag-0.75Cu and Sn-2Ag-0.75Cu-3Bi solder to investigate factors
involved in degradation of joint strength. Our analytical method consisted of
using an SEM to observe changes in solder structure and using an EPMA to
perform elemental analysis of the joint interface alloy layer. Our analyses
indicate that changes in the solder structure include structural changes in the
Ag3Sn network. Our results also show a link between the structural
degradation that follows reliability tests and abnormal growth in the alloy
layer. |
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14 (02.10.1)
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Factors leading to ionic migration in lead-free solder |
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Abstract
The factors leading to ionic migration under investigation by this
report are those factors stemming from cathodic deposition characteristics, anodic
dissolution characteristics, and the surface texture and rest potential of lead-free solder.
The results of this investigation indicate that lead-free solder suppresses the cathodic
deposition reaction by forming a stable passivity film that prevents the anodic dissolution
reaction. These results indicate that lead-free solder can be considered more reliable than
conventional leaded solder with regard to ionic migration. |
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13 (.2.3.15)
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The current status of lead-free soldering. |
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Abstract
Lead-free solder mounting technology took off in the Japanese market during the year
2000, and as the year 2001 ushered in the 21st century, a large number of products
with lead-free solder mounting were already appearing on store shelves. Elsewhere, EU
deliberation on the draft of the WEEE/RoHS directive moved into the home stretch, and
was scheduled for final approval by vote in the EU assembly in April 2002. The course
had been set for adopting lead-free solder for surface processes of parts as well,
bringing the possibility of lead-free solder mounting very close to achievement. This
article will provide a view of the current state of technological progress in lead-free
soldering, both in Japan and abroad, and will discuss future prospects for the technology. |
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12 (01.10.1)
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Evaluating lead-free plating using gas corrosion tests |
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Abstract
For this report, we have studied the plating of lead-free solder that industry has
been trying to incorporate. We have carried out gas corrosion tests, and we present our
findings on visible changes (discoloration), wettability and surface analysis. |
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12 (01.10.1)
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Evaluating ionic migration in lead-free solder using the Quartz Crystal Microbalance Method |
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Abstract
Since ionic migration is one form of electrochemical corrosion, we have been
applying Quartz Crystal Microbalance Method (QCM) as a tool for analyzing the growth process of ionic migration in lead-free
solder. Our results indicate that lead-free solder is superior to conventional lead solder
in resisting migration. This migration resistance is a result of tin, the main element of
lead-free solder, forming a stable passive film on the surface of the electrodes, and thus
suppressing both metallic dissolution at the anode*1 (the elution electrode), as well as
metallic deposition at the cathode*1.
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11 (01.4.1)
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Evaluation results on reliability of lead-free solder - Tabai Espec efforts to develop viable lead-free solder -
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Abstract
We at Tabai Espec have undertaken the challenge of creating lead-free solder for use in
PCB's to protect the environment. Setting out to obtain basic selection data for the
various types of lead-free solder, we have evaluated mounting and reliability of lead-free
solder for both reflow soldering and flow soldering.
Our results show that the solderability of lead-free solder is inferior to conventional
solder, and that for lead-free solder, more study is needed on temperature control in the
mounting process as well as on surface treatment of parts.
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