Preparation Of Surface Microstructure Of Biomimetic Fish Scale And Ice Friction Property

Most of the organisms in nature have gradually formed unique functional microstructures during the long period of evolution.Functional surfaces prepared based on these microstructures possess very high research value in the fields of self-cleaning,oil-water separation and friction control,which have already been widely used in medicine,aviation and industry.As a branch of tribology,ice friction has always been the main research in transportation,polar investigation and winter sports.Thus,it is of great practical significance to explore the theoretical basis and friction characteristics of ice friction.In this paper,the biomimetic preparation of the microstructure on the fish scale surface was realized on the stainless steel by nanosecond laser technology based on the morphological characteristics of the surface microstructure of natural aquatic fish scale.The performance and microstructure on the surface of fish scale were controlled.Besides,the ice friction characteristics of the biomimetic fish scale surface were tested.First of all,the microstructure of fish scale was observed to determine the morphology characteristics and the size of the biomimetic microstructure.The laser processing parameters were optimized to realize the preparation of the biomimetic surface microstructure of fish scale combined with the principle and characteristics of nanosecond laser technology.The results showed that the laser power,scanning speed and scanning times all affect the morphology and size of the microstructure.The optimized laser processing parameters were as follows: laser power=10W,scanning speed=200mm/s and scanning times=12.Secondly,the biomimetic fish scale surface prepared by nanosecond laser showed timedependent property from superhydrophilicity to superhydrophobicity.The heating treatment changed the deposition of non-polar carbon layer on the surface of microstructure,which realized the regulation of surface wettability.The hydrophobicity of biomimetic fish scale surface increases as the heating time increases.Fluorosilicone modification reduced the free energy of sample surface and further reduced the adhesion of surface to water droplets.The contact area could be changed by adjusting the distance between microstructures.And as the microstructure spacing increases,the contact area decreases.Finally,the effects of microstructure,wettability,adhesion,contact area,normal pressure and sliding speed on the ice friction coefficient were investigated.The results showed that the unique microstructure on the biomimetic fish scale surface could reduce the shear force of water film during the sliding process,which has a certain friction reducing effect compared with the smooth surface.Both of the transition of wettability and adhesion would change the water film morphology and further improve the ice friction characteristics.With the increase of contact area,the ice friction resistance and friction coefficient both gradually increased.The increasement of normal pressure and sliding speed could accelerate formation rate of water film and thicken the water film continuously,which produced a certain lubrication effect and reduced the ice friction coefficient.