Micromorphology of metallic surfaces for hydrophobicity by waterjet-guided laser processing

Waterjet-guided laser processing is a novel machining technique for metallic materials. To investigate and analyse the effects of processing parameters on surface topography change, micro-texturing evolution, and hydrophobicity, micromorphology machining experiments were conducted on stainless steel using self-developed waterjet-guided laser processing equipment. Nd:DPSS laser system with repetition frequency of 20-120 kHz and maximum power of 50W is used in the equipment. A scanning electron microscope (SEM) is used to measure surface topography. Energy-dispersive spectrometer (EDS) is used to evaluate the material composition of processing zone and no processing zone. The effects of grid spacing and laser power coupled into the jet are examined and processing conditions for hydrophobicity are provided. There was oxidation and no crack on the kerf edge. The surface contact angle dramatically increases from 92.94 to 138.41 degrees with the decreasing of the grid size. It has been shown that waterjet-guided laser processing yields textures with a hydrophobic surface and is suit for micro-texture micro-machining.