Abstract
In our previous paper, the dissolution of solid copper into liquid tin and the influences of the additional elements to liquid tin were reported as a fundamental research of soldering. The purpose of this study is to make clear the growth process of an alloy layer formed between solid copper and liquid tin which has influence upon the mechanical properties of solidered joints. A static study has been made on the process of the growth of alloy layer under the condition with or without dissolution of solid copper during the reaction. The results obtained from the experiments made at different temperature in the range 320°∼580°C are summerized as follows:
(1) A formula W=b×ta between thickness of alloy layer W and reaction time t was derived for the growth of alloy layer and the values of a were 0.38 for η phase and 0.53 for ε, δ, and γ phases, under the condition without dissolution of solid copper in copper saturated liquid tin alloys.
(2) The temperature dependence of b in the formula W=b×ta was found to obey an activation process of the Arrhenius type.
(3) Under the condition with dissolution of solid copper, the value of a was 1.0, that is, the thickness of alloy layer increased in proportion to the reaction time.
(4) It has been made clear by microscopic observation that under the condition with dissolution, the alloy layer grew in intensive competition with the dissolution of solid copper.
