Influencing the contact angle during brazing by direct laser interference structured textures on the substrate surface

Direct Laser Interference Patterning (DLIP) is used to generate textured stainless steel surfaces to control the wettability of a liquid nickel-based brazing alloy. The interference of two laser beams leads to periodic line-like structures with a spatial period of 6.0 µm. A maximum structure depth of 2.0 µm is reached by controlling the processing parameters. Moreover, the generation of laser induces periodic surface structures (LIPSS) with a period of ∼ 800 nm is observed on top of the DLIP structures. Depending on the produced texture depth, the contact angle of the molten metal is increased from 13° up to 96°. This allows adjusting the contact angle for various brazing and soldering applications and can also be used as a filler metal stop.