Study On Construction Of Superhydrophobic Surface Of Aluminum/Magnesium Alloy And Its Corrosion And Wear Resistance

Aluminum/magnesium alloys are the main metal materials to realize the lightweight of weapons and equipment.However,aluminum/magnesium alloys are easily corroded and weared,which can cause weapon performance failure and even endanger the safety of soldiers,thus limiting its application in the field of lightweight weapons and equipment.Surface treatment technology is currently the most direct and effective means to improve the corrosion resistance and wear resistance of metals.Among them,the bionic superhydrophobic surface not only has excellent superhydrophobic properties,but also shows potential application prospects in other fields,including self-cleaning,antifouling,drag reduction,frost resistance,corrosion resistance and wear resistance etc.In recent years,the research on superhydrophobic surfaces has made great progress,but most of the existing preparation methods require special processing equipment,complicated processes and harsh conditions,which hinders the largescale production of superhydrophobic surfaces.Therefore,in-depth research on the corrosion resistance and wear resistance mechanism of superhydrophobic surfaces is of great significance for broadening the application of aluminum/magnesium alloys in weapons and equipment.This paper takes the representative 7075 aluminum alloy and AZ31 B magnesium alloy as the research object,and uses the method of combining EDM technology and low surface energy material modification to design the micro/nano composite structure of the metal surface,making the superhydrophobic surface of aluminum/magnesium alloys has excellent corrosion resistance and wear resistance.With the help of testing methods such as FESEM,EDS,FT-IR and XPS,the superhydrophobic surface morphology,structure,and chemical composition are tested and characterized.Systematic research on the superhydrophobic surface of aluminum/magnesium alloys in the mechanism aspects of the surface wettability,mechanical stability,chemical stability,corrosion resistance and wear resistance and so on has been carried out.The main research contents and conclusions are as follows:(1)The feasibility of electrical discharge machining(EDM)to create superhydrophobic surface has been studied,which provides a theoretical basis for the design of superhydrophobic surface structure in aluminum/magnesium alloys.(2)Optimization parameters of preparing superhydrophobic surface.The mapping relationship between the EDM parameters and wettability of the aluminum/magnesium alloys surface was established.Orthogonal experiment was used to optimize the preparation process parameters,and the results showed that the primary and secondary order of EDM parameters affecting wettability was: pulse interval>power tube number>pulse width.The best combination of EDM parameters was obtained,and the aluminum/magnesium alloy superhydrophobic surface prepared by the best preparation process parameters all conformed to the Cassie model.(3)Research on the formation mechanism of superhydrophobic surface of aluminum/magnesium alloys.The rough structure and the array structure of the aluminum/magnesium alloys superhydrophobic surface conform to the dual-scale and multiscale microstructures,respectively.With the help of FESEM,EDS,FT-IR and XPS and other test and characterization methods,the results show that a large amount of carbon elements detected on the surface of aluminum/magnesium alloys are caused by the successful modification of low surface energy substances.Therefore,the microstructure of the aluminum/magnesium alloys surface and its interaction with substances with low surface energy are the internal mechanism for the formation of superhydrophobic surfaces.In addition,the superhydrophobic surface of aluminum/magnesium alloy has excellent chemical and mechanical stability.(4)Research on corrosion resistance of aluminum/magnesium alloys superhydrophobic surface.Under the condition of 3.5 wt.% Na Cl solution,an electrochemical workstation was used to test the corrosion resistance of the aluminum/magnesium alloys superhydrophobic surface.Compared with the aluminum/magnesium alloys matrix,the corrosion potential of the superhydrophobic surface moves in the positive direction,and the potentiodynamic polarization curve also moves to the left,resulting in a decrease in the self-corrosion current density,which indicates that its corrosion resistance has been improved.Since the superhydrophobic surface of the aluminum/magnesium alloys conforms to the Cassie model,a large number of micro/nano composite structures are distributed on the surface.This structure can effectively store a large amount of air to form an "air cushion",which effectively prevents the direct contact between the corrosive solution and the superhydrophobic surface,and greatly reduces the actual contact area,thereby improving its corrosion resistance.(5)Research on the anti-wear properties of aluminum/magnesium alloys superhydrophobic surface.Under the test conditions of different loads and different friction speeds,the UMT-2 multifunctional mechanical test system was used to study the anti-wear performance of the aluminum/magnesium alloy superhydrophobic surface.Compared with the matrix,under the same test conditions,all aluminum/magnesium alloys superhydrophobic surfaces exhibit excellent wear resistance.Microscopic characterization and research have found that this is due to the large number of micro/nano structures distribute on the superhydrophobic surface of the aluminum/magnesium alloys during the frictional contacting process,resulting in the actual contact area being much smaller than that of the matrix,which effectively reduces friction and wear and thereby improves its anti-wear performance.