Preparation Of Superhydrophobic (Color) Stainless Steel Surface And Performance Study By Pre-activation Treatment Combined With New Ultrasonic Etching Technology

It is a common method to prepare super-hydrophobic stainless steel by rough micro-nanostructures formation via chemical etching and the subsequent modification of low surface energy materials.However,due to the uneven thickness of the oxide film on the surface of the stainless steel,and scratch grooves easily generated during the production process.the chemical etching is extremely uneven,and the roughness of the stainless steel surface is unevenly distributed.So the etching effect is poor and takes a long time.Based on the current situation,the following two superhydrophobic modification systems for AISI 304 stainless steel has studied.Using a combination of pre-activation treatment and chemical etching,the oxide film and the groove with uneven thickness on the surface of the stainless steel are removed by the pre-activation treatment process.Then,it is etched by a mixed etching solution of Fe Cl₃·6H₂O and HCl,and a micro-nano composite structure which is more uniform compared to that on direct etching surface is prepared on the surface of the stainless steel.The effects of pre-activation treatment time,etching time,etching solution ratio and etching temperature on the micro-nanostructure of stainless steel surface were investigated by means of water contact angle measurement,SEM,AFM,EIS and dynamic potential polarization curve.The results show that when the activation time is 3 min,the etching temperature is 35°C,and the etching time is 1 h,the stainless steel test piece has the best hydrophobic properties,with water contact angle can up to 155.30°.Furthermore,the feasibility of preparing color super-hydrophobic surface on the etched substrate was studied.The experimental results show that the electrochemical square potential wave coloring can retain the rough structure of the surface and obtain the color superhydrophobic surface with water contact angle of 151.83?.Based on the improved pretreatment method,the physical sandblasting process was further introduced into the etching process.The micro-nano composite voids with more uniform distribution on the surface of stainless steel were fabricated by nano-particle ultrasonic-assisted etching process than under conventional etching conditions.The effects of ultrasonic etching ways and etching time on the surface morphology,superhydrophobic properties and corrosion resistance of stainless steel were investigated.Through experimental comparison,it is found that the time of forming rough structure on stainless steel substrate surface can be effectively reduced by ultrasonic treatment.The etching effect can be effectively improved by adding nano-Si O₂particles.After the rough surface is modified by low surface energy materials,the water contact angle of stainless steel surface can reach 161.41?,and the corrosion resistance can also be improved.