Related Gold Paste Blog Articles
Au-mazing Solutions: How AuLTRA® MediPro is Setting the Gold Standard for Medical Device Soldering
Indium Corporation's AuLTRA® MediPro product line offers high-performance gold-based solder materials for medical devices, ensuring reliability and precision in critical applications like pacemakers, hearing aids, and Continuous Glucose Monitors (CGM). With properties such as superior oxidation and corrosion resistance, biocompatibility, and hermetic sealing, AuLTRA® MediPro guarantees long-lasting connections in wearable, implantable, and industrial devices. This complete range of materials, including paste, wire, preforms, and ribbon, upholds the "Gold Standard" in medical technology, certifying quality, safety, and dependability.
Read MoreSPIE Photonics West 2024
Indium Corporation® featured our Precision Au-Based Die-Attach Preforms at SPIE Photonics West 2024, the world’s premier event for lasers, biomedical optics and biophotonic technologies, quantum, and optoelectronics...
Read MoreUsing the Density Technique to Estimate Gold Mass Fractions in Gold Alloys with Silver and Copper
Folks, My second email from Adriana Re using density to determine gold mass fraction is below. She asked if we could communicate in French. The translations ar...
Read MoreCalculating the Mass Fraction of Gold in a Gold Alloy
Adriana writes, "Dear Dr. Ron. I’m trying to program the equation for determining the weight fraction of gold in scrap metal from the density of the scrap..."
Read MoreBack to Basics: Au-Based Alloys
Indium's “Gold Standard” refers to the overall reliability and quality you can expect from our gold-based solder materials. Gold-based alloys offer strong solder joints, excellent corrosion and oxidation resistance, and good thermal and electrical transfer. Our gold-based alloy library includes a wide variety of gold-based solders suitable for any application at hand, such as 80Au20Sn, 88Au12Ge, 96.8Au3.2Si, 82Au18In, and 100Au.
Read MoreFeatures & Benefits
- Highest tensile strength of any solder
- High melting point is compatible with subsequent reflow processes
- Pb-free
- Superior thermal conductivity
- Resistance to corrosion
- Superior thermal fatigue resistance
- Good joint strength
- Excellent wetting properties
- Resistance to oxidation
- AuSn is compatible with precious metals
- AuSn is RoHS compliant
Gold-Tin Solder Paste
AuSn Alloys:
- 80Au20Sn
- 79Au21Sn
- 78Au22Sn
- 77Au23Sn
Powder Sizes:
- Type 2 (-200/+325)
- Type 3 (-325/+500)
- Type 4 (-400/+635)
- Type 5 (-500/+635)
- Type 6 (-635)
- Type 6 SGS (5–15μm w/less than 10% overs/unders)
- Type 7 SGS (2–11μm w/less than 10% overs/unders)
No-Clean Flux:
- AuLTRA™ 5.1 (used in high-power LED and MEMS applications)
- Indium10.8HF (accommodates higher processing temperatures required by the electronics industry)
- RMA-SMQ51A (for difficult to solder surfaces in die-attach)
- NC-SMQ75 (halogen-free and low-residue; requires <10ppm oxygen)
Water-Wash Flux:
- AuLTRA™ 3.2 (used in high-power LED applications)
- Indium3.2HF
Low-Volume Packaging:
- Jars (10g per jar)
- Syringes (5cc syringes)

Gold-Tin (AuSn) Solder Paste
Gold-Tin (AuSn) Solder Paste is generally used in applications that require a high-melting temperature (80Au20Sn has a melting point of 280°C / 556°F). It can be made into a variety of solder paste forms with various options to address specific applications. It exhibits good thermal fatigue properties and is used in many applications that require high tensile strength and high corrosive resistance. In step soldering applications,Gold-tin (AuSn) Solder Paste will not melt during a subsequent low-temperature reflow process.