Solder Alloys

Solder Alloys

Since our founding in 1934, Indium Corporation has been the world’s leader in specialty solders and alloy development. Our R&D staff, including several Ph.D. metallurgists, work with our core set of metals to develop alloys that will address the latest soldering and sealing challenges.

Introducing Two New Alloys Solutions

Consistent with our reputation for developing innovative new alloys, Indium Corporation has introduced two new alloys solutions:

Durafuse LT

Durafuse LT is a patent pending two temperature alloy system designed to provide high-reliability in low-temperature applications. Durafuse LT provides improved drop shock resilience, outclassing bismuth-tin (BiSn) or bismuth-tin-silver (BiSnAg) alloys, and performing better than SAC305 with optimum process setup. Durafuse LT is made up of a low-melting indium-containing alloy and a higher-melting SAC alloy. The required peak reflow temperature is under 210°C. The SnInAg alloy initiates joint fusion while the SAC alloy provides enhanced strength and durability. Durafuse LT is ideal for high-reliability applications which utilize thermally sensitive components.

Durafuse LT Features:
  • Excellent drop shock reliability – comparable to SAC
  • Reflow below 210°C
  • Melting temperature above 180°C
  • Good mechanical shear strength up to 150-165°C
  • Good thermal and electrical conductivity

For more information about Durafuse LT, please download our product data sheet.

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Indalloy®292

Indalloy®292 is an alloy engineered to provide advanced reliability for high-performance applications. It has excellent thermal cycling performance at -40/150°C conditions, high shear strength, and low solder joint cracking. The elimination of pinholes improves joint appearance.

When paired with Indium8.9HF solder paste, Indalloy®292 provides outstanding printability, stability, and enhanced SIR. For more information about Indalloy®292 with Indium8.9HF, please download our product data sheet.

There are also other metals that can be used in these alloys:

  • Antimony (Sb)
  • Silver (Ag)
  • Germanium (Ge)
  • Cadmium (Cd)
  • Copper (Cu)
  • Zinc (Zn)

The first criteria for choosing a solder is usually the melting temperature, but our solder alloy selector guide also allows you to sort by operational temperature and process temperature. Additionally, you can sort you alloy selection by Pb-free and/or Cd-free alloys, as well as by alloys that are RoHS compliant.

MC Pure Indium

Six Alloy Families:

Gallium

Since gallium and gallium alloys are generally liquid at room temperature, they are not generally used for solder applications, but find a home with thermal applications. Gallium is also a replacement for the mercury (Hg) in batteries.

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Indalloy® # Composition Liquidus/Solidus Temperature (°C)
51E 66.5Ga/20.5In/13Sn 11 Eutectic
60 75.5Ga/24.5In 16 Eutectic

Bismuth

Most bismuth alloys are considered low-temperature and many of them are Pb-free. Although bismuth is considered to be fairly brittle, BiSn and BiSnAg are widely used in step-soldering applications and other applications where a lower temperature is required.

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Indalloy® # Composition Liquidus/Solidus Temperature (°C) Solidus Temperature (°C)
281 58Bi/42Sn 138 Eutectic  
282 57Bi/42Sn/1Ag 140 139

Indium

Indium is a very versatile metal, often used for soldering to gold, thermal applications, low-temperature solders, bonding to ceramics, hermetic and cryogenic sealing, and CTE mismatch.

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Indalloy® # Composition Liquidus/Solidus Temperature (°C) Solidus Temperature (°C)
1E 52In/48Sn 118 Eutectic  
1 50In/50Sn 125 118
290 97In/3Ag 143 Eutectic  
2 80In/15Pb/5Ag 154 149
4 100In 157 Melting point  
204 70In/30Pb 175 165
205 60In/40Pb 181 173
227 77.2Sn/20In/2.8Ag 187  
7 50In/50Pb 210 184
3 90In/10Ag 237 143
164 92.5Pb/5In/2.5Ag 310 300

Tin

Tin is the basis for most electronics grade solders. It has excellent wetting, but is not recommended for soldering to thick Au-plating since the tin will leach or scavenge the gold. Adding antimony (Sb) to tin will give higher creep strength at temperatures up to 100°C.

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Indalloy® # Composition Liquidus/Solidus Temperature (°C) Solidus Temperature (°C)
106 63Sn/37Pb (Sn63) 183 Eutectic  
121 96.5Sn/3.5Ag 221 Eutectic  
133 95Sn/5Sb 240 237
256 96.5Sn/3Ag/0.5Cu (SAC305) 220 217

Lead

Alloys containing lead are not RoHS-compliant, so alternatives are being sought to replace the SnPb alloys of the past. Several applications require higher temperatures and can still use lead.

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Indalloy® # Composition Liquidus/Solidus Temperature (°C) Solidus Temperature (°C)
151 92.5Pb/5Sn/2.5Ag 305 298
164 92.5Pb/5In/2.5Ag 310 300

Gold

Gold is considered a noble metal and can be used in fluxless reflow environments. Pure gold has a melting point of 1,064°C but can be alloyed with tin (Sn), silicon (Si), or germanium (Ge) for lower melting points. 80Au/20Sn, a eutectic alloy is by far the most popular gold-based alloy.

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Indalloy® # Composition Liquidus/Solidus Temperature (°C)
182 80Au/20Sn 280 Eutectic
183 88Au/12Ge 356 Eutectic
184 96.8Au/3.2Si 363 Eutectic
200 100Au 1,064 Melting point

Paste, preforms, and wire are the most popular forms of solder we supply. Most of the alloys or pure metals listed can be supplied in these forms.

We also have a variety of Solder Research Kits available for initial testing in your application. These kits are available as wire, ribbon (for cutting preforms), and paste, and will get you started in your selection process.

Our globally based Applications Engineering teams are also available for consultation by phone, email, or onsite visits.