Influence of micro-nano multiscale surface texture on wettability of Ni-based droplets at high temperature

The wetting behavior of sprayed droplets on textured surfaces is the key factor that determines the adhesion strength of sprayed coatings. The 3-D roughness parameter could be used to describe the textured surface and build the relationship with the wettability of sprayed droplets. Micro and nano sale 3-D roughness parameter of surface texture could be acquired separately through the classification extraction due to the micro-nano multiscale roughness feature of laser textured surface. The contact angle of the sprayed droplets at high temperature on a textured surface with different patterns was studied. The results show that the contact angle of the sprayed droplets increases with increases in the amplitude parameter Ssk and the spatial parameter Str, while it decreases with increases in the amplitude parameter Sku and spatial parameter Sal. The nanoscale debris of the laser textured surface are beneficial for improving the amplitude parameter Sku, which can increase the wettability of sprayed particles with the substrates. •Contact angle of spray droplet has regular relationship with amplitude parameters and spatial parameters.•Wavelength restriction method can effectively separate waveform and roughness parameters.•Nano scale protruding around the micro scale dimples is useful to the wetting of sprayed droplets.