JPS56144893A - Solder alloy for fitting lead on silver electrode - Google Patents

Abstract

PURPOSE:To improve the soldering property of Sn-Ag-Sb-Pb solders without harming the characteristics, by specifying the composition. CONSTITUTION:The solder alloy is composed of, by wt., 15-65% Sn, 0.5-3.5% Ag, <=0.5-3.0% Sb, and the remainder of Pb. This solder has a soldering property which can sufficiently be adopted to high speed soldering without harming the silver disolving, heat resistance and solid diffusion of silver. When the Sn content is less or more than the above, the improvement effect of the soldering property becomes less in the former case, and the temperature rises higher than the required liquidus temperature in the latter case, in addition, it is required to add a large amount of silver to prevent silver disolving and, at the same time, it makes the liquidus temperature higher. When the Ag content is less or more than the above mentioned range, the diffusion melting of silver cannot be controlled sufficiently in the former case, furthermore, it raises the liquidus temperature in the latter ease. When the Sb content is less or more than the above mentioned range, no advantageous effect is expected in the adhering strength in the former case, and the soldering property becomes inferior in the latter case.