Pb-Free

Available Lead-Free Solder Alloys

Indium Corporation offers custom alloy development for specific temperature requirements and for special metallizations as well as non-metal bonding applications. Indium Corporation has been developing lead-free and cadmium-free alloys for many years. We have over 25 standard alloys, including our three patented alloys (see notes below). Or we can develop an alloy for your specific application.

If you would like to evaluate several of these alloys, consider our Wire Selector Kit, which offers many choices without cadmium or lead.

Low Temperature Solders

Indalloy No. Composition Solidus (oC.) Liquidus (oC.) U.S. Patent Comments
19 51In / 32.5Bi / 16.5Sn 60 (eutectic) Lowest melting point alloy; uncommon applications.
162 66.3In / 33Bi 72 (eutectic) Poor wetting.
174 57Bi / 26In / 17Sn 79 (eutectic) Marginal wetting.
27 54.02Bi / 29.68In / 16.3Sn 81 (eutectic) Marginal wetting.
1E 52In / 48Sn 118 (eutectic) Lowest melting point solder with good wetting.
281 58Bi / 42Sn 138 (eutectic) Good thermal fatigue performance; established history.

Mid-Range Temperature Solders

Indalloy No. Composition Solidus (oC.) Liquidus (oC.) U.S. Patent Comments
231 86.5Sn / 5.5Zn / 4.5In / 3.5Bi 174 186 5,455,0043 Zn causes high drossing; corrosion concerns; not available as paste.
226 83.6Sn / 8.8In / 7.6Zn 181 187 5,242,6583 Zn causes high drossing; corrosion concerns; not available as paste.
227 77.2Sn / 20.0In / 2.8Ag 175 187 5,256,3703 & 5,580,5203 Not for use over 100oC due to 118oC Sn / In eutectic; cost.
254 86.9Sn / 10.0In / 3.1Ag 204 205 Lower indium mitigates Sn / In eutectic problem.
201 91Sn / 9Zn 199 (eutectic) Zn causes high drossing, not available as paste.

Higher Temperature Solders

Indalloy No. Composition Solidus (oC.) Liquidus (oC.) U.S. Patent Comments
2411 95.5Sn / 3.8Ag / 0.7Cu 217 220 Popular SAC alloy for SMT assembly.
246 95.5Sn / 4.0Ag / 0.5Cu 217 225 Petzow (German) prior art reference makes this alloy patent-free.
2521 95.5Sn / 3.9Ag / 0.6Cu 217 225 NEMI promoted alloy
2561 96.5Sn / 3.0Ag / 0.5Cu 217 220 Reduced silver SAC alloy.
232 93.6S / 4.7A / 1.7Cu 217 244 5,527,6284 Original Iowa State Ames Lab SAC alloy.
249 91.8Sn / 3.4Ag / 4.8Bi 211 213 5,439,6394 Board & component metallizations must be completely Pb-free.
121 96.5Sn / 3.5Ag 221 (eutectic) Simple binary alloy solder has history of use; marginal wetting.
2442 99.3Sn / 0.7Cu 227 (eutectic) Inexpensive, popular use in wave soldering.
129 99Sn / 1Sb 232 235 Antimony addition increase strength.
131 97Sn / 3Sb 232 238 Antimony addition increase strength.
133 95Sn / 5Sb 235 240 Antimony addition increase strength.
209 65Sn / 25Ag / 10Sb 233 (melting point) Motorola-developed “J-alloy” die attach solder; very brittle.

High Temperature Solders

Indalloy No. Composition Solidus (oC.) Liquidus (oC.) U.S. Patent Comments
182 80Au / 20Sn 280 (eutectic) Highest temperature Pb-free.