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Values presented in the table below are for some of
the most commonly used solders. With the push for lead-free (Pb-free) versions that
conform the the RoHS1 initiative that will be in effect in Europe in
the summer of 2006, new alloys have been developed that use little or no lead at
all. For those application, this resource compiled by NIST2 and the Colorado
School of Mines will be very helpful.
 A big problem with
lead-free (aka Pb-Free) solder is that the higher the tin content, the more likely
the growth of "tin whiskers."
This phenomenon where tiny tendrils grow out of the solder is still not fully understood.
The problem is that short circuits can be established between adjacent conductors,
and within a high density connector or a fine-pitch IC package. Some military and
space-based platforms ban the use of Pb-Free solders for that reason.
See my handy tip for holding solder while manually soldering.
In the chart below, any solder compound that does not have a "Pb" component is
lead-free.
| 5Sn-95Pb
|
307 |
585 |
| 0.5Sn-92.5Pb-2.5Ag |
280 |
536 |
| Sn/5Sb |
243 |
469 |
| 100Sn3
|
232 |
450 |
| 99.3Sn-0.7Cu |
227 |
440 |
| 96.5Sn-3.5Ag
|
221 |
430 |
| Sn/3.0Ag/0.5Cu |
219 |
426 |
| Sn/3.8Ag/1.0Cu |
217 |
423 |
| Sn/3.5Ag/1.0Cu/3Bi |
213 |
415 |
| 50In-50Pb
|
209 |
402 |
| 45Sn-55Pb
|
204 |
400 |
| 55Sn-45Pb
|
193 |
379 |
| 60Sn-40Pb
|
186 |
368 |
| 63Sn-37Pb
|
183 |
361 |
| 62Sn-36Pb-2Ag
|
179 |
354 |
| 97In-3Ag
|
143 |
289 |
| Sn/57Bi |
139 |
282 |
| 52In-48Sn |
118 |
244 |
1: Reduction of Hazardous Substances
2: National Institute of Standards and Technology
3: Pure tin
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