Chemical modification is usually utilized for preparing superhydrophobic SiC surfaces, which has the problems of long processing time, high environmental contamination risk, and high cost. To enhance the condensation heat transfer efficiency of SiC, the superhydrophobic SiC surface was fabricated through laser texturing and heat treatment. In this study, the SiC surface was processed by laser texturing with a nanosecond laser, followed by heat treatment. Surface microstructures and compositions were investigated with SEM and XPS, and the heat transfer coefficient of the superhydrophobic SiC surface was tested. The results indicated that the laser-textured SiC surface had a super hydrophilic contact angle of 0°; after heat treatment, SiC ceramic became superhydrophobic (surface contact angle reaches 164°) because organic contamination on the original SiC surface could be cleaned by using laser texturing, which caused a chemical reaction and the formation of SiO₂ on the surface. Moreover, the distribution of relatively low-energy SiO_X was formed after heat treatment; then, SiC ceramic became superhydrophobic. Due to the formation of nanoscale sheet-like protrusion structures by heat treatment, the SiC superhydrophobic surface exhibited typical dropwise condensation, and the condensation heat transfer coefficient reached 331.8 W/(m²·K), which was 2.3 times higher than that of the original surface.

During the laser surface texturing process, scanning overlap is usually misused, because it cannot only be dimple overlap, but also can be laser spot overlap. Experiments were conducted to investigate the relationship between laser spot overlap and dimple overlap during laser surface texturing. Moreover, the effect of dimple overlap on the laser textured microstructures, wettability, and corrosion performances of stainless steel was analyzed. The results have shown that, due to changing radiation conditions, the dimple diameter and dimple overlap varied in a non-linear way with the increase in laser spot overlap. Furthermore, the variation of dimple overlap rather than laser spot overlap had a direct effect on roughness, wettability, and corrosion resistance. When the dimple overlap was greater than 55%, the surface reached the superhydrophobic state and the maximum apparent contact angle was 162.6°. When the dimple overlap was 83.52%, due to passivation layer formed by laser remelting deposition and oxides compaction, corrosion current density was 2.8 × 10⁻⁸ A·cm⁻², which was 4% of the original value. Consequently, it was determined that it is easier to control the surface roughness, wettability, and corrosion resistance via dimple overlap rather than laser spot overlap in laser surface texturing process.