Dissimilar Metal Joining of Cu and Fe Using Super-Spread Wetting into Surface Fine Crevice Structures

Abstract

Recently, our group employed surface fine crevice structures produced on Cu metal substrates using either laser irradiation or the reduction-sintering of oxide powders to induce region-selective super-spread wetting as a means of joining these substrates. The present work expanded the scope of this method by joining Cu and Fe substrates. Laser irradiation was found to permit the joining of Cu and Fe but generated voids at the join interface. In contrast, the reduction-sintering of mixed oxide powders allowed joining with essentially no voids. Thus, the latter technique is superior to laser irradiation when joining dissimilar metals.

Fig. 10 A cross-sectional SEM image of the joint between Fe and Cu substrates having surface fine crevice structures produced by reduction sintering of a CuO–Fe₂O₃ mixture and EDX elemental maps for Sn, Fe and Cu.