Effect of rosin content on rosin-based fluxes for Zn20Sn solders

The poor wetting of zinc-based alloys has become the bottleneck restraining their extensive applications. In this paper,a new flux was produced by adding proper amounts of organic acid,solvent,corrosion inhibitor,and surface active agent to improve the wetting properties of Zn20Sn solder. The results showed that when the rosin content was within the range of 40%-60%,the physical stability,inadhesion and corrosion properties of the flux could meet the requirements of relevant national standards. With the increasing of the rosin content,the spreading area and spreading ratio of the Zn20Sn solder increased first and then decreased. When the rosin content was about 55%,the spreading area and spreading ratio of the Zn20Sn solder reached the maximum values as 70.3 mm² and 87%,respectively. And no apparent defects occurred in the resultant joint, indicating that the flux benefited to enhance the soldering effects of Zn20Sn solder.