Abstract
Testing methods were studied for severe estimation of solderability of electroplated metals. The vertical immersion testing method was found to be simpler and more reliable than horizontal one. The lower half of each specimen (25×25×0.25mm) was immersed into a sufficient volume of molten solder after flux treatment. A solution containing 25wt.% water-white rosin and 75wt.% isopropyl alcohol free from additives was used as the flux. The solder used was the normal 60%Sn-40%Pb alloy. Soldering temperature was kept at 230±1°C and specimens were immersed into the solder bath for 1±0.1sec. In order to obtain highly reliable data it was necessary to control the bath temperature and immersion time accurately. The solderability was classified into five grades from these three points of view: spreading area, wetting area percentage and appearance of soldered test panel surface. It was found that the testing method proposed here could distinguish even a slight difference in solderability due to very delicate variations in electroplating processes.
