2015 Volume 56 Issue 11 Pages 1852-1856
We have investigated metal–metal joining using “unusual wetting”, in which a liquid metal spreads by capillary action on a porous metal surface layer formed under atmospheric oxidation–reduction. Although oxidation–reduction creates an adequate porous structure for “unusual wetting”, it is difficult to subject only a specific area to atmospheric oxidation–reduction treatment, and region-selective “unusual wetting” and joining are not achieved. In this work, we propose the use of laser, which is able to treat regions selectively, to form a suitable structure for “unusual wetting”. A fine asperity structure was observed on the Cu substrate surface after laser treatment. This structure was termed a “surface fine crevice structure”. The wettability of the laser-treated Cu substrate by liquid Bi was determined to confirm region-selective “unusual wetting” on the “surface fine crevice structure”. We also joined two Cu substrates by “unusual wetting” after creating a “surface fine crevice structure”.