Abstract
Gold-silver alloy solder is a tin based alloy with silver white metallic luster, soft texture and strong ductility. Gold-silver alloy solder has many excellent properties, such as high yield strength, non-toxicity, good conductivity, corrosion resistance, suitable welding temperature and low viscosity. These properties make it widely used in electronic industry, automobile radiator, heat exchanger, food and beverage packaging. At the same time, it reduces the cost and environmental pollution.
Gold-Silver Alloy Solder in the Past
- In 3000 B.C., it was simply used as a coating on bronze ware to prevent serious deformation of bronze ware.
Figure 1. Gold-Silver Alloy Solder's Application in the Past
- In 700 BC, it was found as the main raw material in China's cold weapons.
Gold-Silver Alloy Solder in the Present
- Electronics industry
- The flaming temperature of Au / Sn eutectic alloy is 280°C. High strength, low flux, high thermal conductivity and conductivity, good wettability, low viscosity, good weldability, high corrosion resistance and creep resistance[1]. Through these methods, the reliability and thermal conductivity of electronic components can be improved. Therefore, it is widely used in the application of ceramic packaging cover sealing and component attachment of microelectronic and optoelectronic components.[1]
Figure 2. Gold-Silver Alloy Solder on Electronic Products
- Automobile radiators and Heat exchangers
- It still has high yield strength at the assembly temperature of 250-260 ℃, so it can be better used in automobile radiator.
FIgure 3. Gold-Silver Alloy Solder on Automobile Radiators and Heat Exchangers
Au / Sn eutectic alloy is not compatible with organic materials because of its high melting point, but its superior mechanical properties make it the best choice[3]. These applications include, but are not limited to, Heat exchangers, cover sealing, RF and DC through connections on optoelectronic packages, and laser diode die connections.[2]
Gold-Silver Alloy Solder in the Future
Only when Gold-silver alloy solder is used correctly can good bonding effect be obtained. Gold / tin preformed die bonding applications are becoming the preferred method for assembling high power laser diodes (LD). Au / Sn will become more and more popular, even indispensable in packaging applications.And it will become the mainstream of electronic welding. [2]
References
[1] Au/Sn Solder Alloy and Its Applications in Electronics Packaging, by Tao Zhou, Tom Boba, Martin Oud and Jia Songliang, Coining, Inc.
[2] Solder Alloy Development for Automotive Radiators ，1972_06, by R. E. BEAL
[3] Aamir, M., Muhammad, R., Tolouei-Rad, M., Giasin, K. and Silberschmidt, V., 2019. A review: microstructure and properties of tin-silver-copper lead-free solder series for the applications of electronics. Soldering & Surface Mount Technology, 32(2), pp.115-126.