| Except owning the advantages of self-coloured stainless steel including excellent corrosion resistance,wear resistance,and toughness over a wide temperature range,the coloured stainless steel can present colorful appearance,optimal visual sense and decoration effect.So it was widely applied in fields of crafts,construction,kitchen utensils,advertising,and daily necessities,etc.However,the oxide film on the surface of stainless steel involved in interference coloration is mainly composed of oxides,which has a high surface energy and is easy to adsorb pollutants,then to affect its decorative effect and corrosion resistance under long-term service conditions.At present,a lot of work has been carried out on super-hydrophobic modification of natural color stainless steel,but few relative works has been reported about super-hydrophobic coloured stainless steel.In this paper,we successfully fabricated coloured super-hydrophobic surface on SS substrate by fluorine-silane modification on the micro-nano roughed INCO-coloured film formed on chemically etched SS substrate.Using water contact angle measurement,SEM,EDX,XPS,potentiodynamic polarization,and simple static immersion test,the influence of chemical etching treatment time,and of chemical repair treatment for the etching substrate before coloring,on the coloring performance of stainless steel substrate and on the hydrophobicity and corrosion resistance of the fluorosilane-modified color surface was discussed.Also the effect of sealing treatment on the hydrophobicity and corrosion resistance of the fluorosilane-modified color surface was investigated.The key influence factors and relative mechanisms in the construction of super-hydrophobic corrosion-resistant coloured stainless steel were summarized.The hydrophobic and super-hydrophobic color stainless steel surfaces with excellent comprehensive performance was successfully obtained.The effect of etching time of etching reagent with composition of 0.96mol/L HCl and 1.11mol/L FeCl3 for 304 stainless steel substrate on the coloring performance,surface micro-structure,chemical composition of substrate,and on water infiltration and corrosion resistance after fluorosilane modification was studied.The results showed that due to the increase of surface roughness after etching,it took a longer time to obtain the ending color,and the end color is slightly changed by etching.After etching,the surface of the colored film still retains the rough structure,and hydrophobic stainless steel surface can be obtained by further modifying with fluorosilane.The comparison between the etching treatments of 10,20,and 30 minutes showed that the water contact angle of the fluorinated coloured surface formed on 20 minutes-etching substrate was the largest,reaching 152.57°,achieving the super-hydrophobic lever.The corrosion resistance of the obtained super-hydrophobic coloured stainless steel was slightly higher than that of the ordinary colored stainless steel.After chemical etching,H2O2 and HNO3 were used to passivate the surface respectively,followed by coloring and fluorosilane modification.The results showed that after repairation treatment,the color of the surface changed little,and the surface roughness decreased with hydrophobicity slightly decreasing,but the surface showed water contact angle greater still higher than 144°.The passivation treatment greatly improved the surfaces' corrosion resistance.After the chromate electrolytic sealing of the surface,the color changed,and the water contact angle continued to decrease(still greater than 137°),however the corrosion resistance was further improved.Therefore,through chemical etching,INCO coloring and fluorine-silane modification,a super-hydrophobic and corrosion-resistant stainless steel surfaces can successfully be prepared.The H2O2/HNO3 oxidation treatment for etched surface and the sealing treatment after coloration,both reduced the roughness and water contact angle of the fluorine-silane modificated-coloured film to some extent,but further improved the corrosion resistance of the sample surface. |
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