The Effect of Reflow Profile on the Soldering Performance of Tin-Bismuth Alloys
Bibliographic record
Abstract
ABSTRACT There is a growing trend towards the implementation of low temperature solders in the surface mount technology (SMT) industry. Tin-bismuth solders are a popular candidate because of their low melting points, but the link between reflow profile and the properties of the reflowed solder joint is not well understood. In this work, printed circuit boards (PCBs) were printed using reflow profiles that have varying time above liquidus (TAL) and peak temperature. The PCBs were then analyzed to see how the reflow profile affected the soldering. The reflowed PCBs were first analyzed for key properties like voiding and wetting. They were cross-sectioned afterward so that their metallurgical properties could be examined. Analysis of the reflowed solder joints revealed that reflow profile had a minimal effect on the intermetallic compound (IMC) layer or the metal microstructure. Furthermore, the samples were cycled between -25 °C and 125 °C for 1000 cycles. All the samples behaved similarly during thermal cycling, indicating that 42Sn58Bi and 42Sn57Bi1Ag are robust alloys which can withstand a wide variety of reflow conditions without it affecting their mechanical properties.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".