​About AuSn20

About AuSn20

High vacuum continuous casting equipment

AuSn20 is often mistaken for a mass ratio of 80%:20% between gold and tin. In fact, the 80%:20% here refers to the molar mass.

AuSn20 is usually used as a brazing solder. The brazing temperature is moderate, and the brazing temperature is only 20-30°C higher than the melting point of AuSn20 (i.e., about 300-310°C). During the brazing process, based on the eutectic composition of AuSn20, a very small overheating can melt and infiltrate AuSn20; in addition, the solidification process of AuSn20 is also very fast. Therefore, the use of AuSn20 can greatly shorten the entire brazing process cycle. The soldering temperature range of AuSn20 is suitable for assembly of components with high stability requirements. At the same time, these components can also withstand subsequent assembly at relatively low temperatures using lead-free solders. The assembly temperature of these solders is about 260°C.

AuSn20 has a high yield strength. Even at temperatures of 250-260°C, its strength is sufficient to meet the requirements of airtightness. AuSn20 has a large proportion of gold (80%) and the degree of oxidation on the surface of the material is low. If a vacuum or a reducing gas mixture such as nitrogen and hydrogen is used during the soldering process, chemical flux is not required. Liquid AuSn20 has a very low viscosity, so it can fill some large gaps. It has good corrosion resistance to lead-free tin solder on gold-plated layers. AuSn20 is similar to the composition of gold-plated layers, so the degree of dissolution of very thin coatings through diffusion is very low, and there is no migration phenomenon like silver. AuSn20 solder also has high corrosion resistance, high creep resistance and good thermal and electrical conductivity.