| As a rapid prototyping technology,3D printing has been applied to manufacture components having complex structures,and has gradually expanded its application scope in aerospace,automotive,biomedicine,and construction fields.In recent years,3D printing technology has developed rapidly,and it is a proven fact that Al,Ti alloys can be manufactured by 3D printing technology in industrial production.Among the3D printing technologies,AlSi10Mg alloys formed by Selective Laser Melting（SLM）have excellent mechanical properties.However,the hardness,wear and corrosion resistance of AlSi10Mg alloy formed by SLM are unable to achieve the purpose of working in some harsh conditions.Plasma electrolytic oxidation,as a kind of surface oxidation technique,has long been utilized for generating hard ceramic coatings to protect aluminum and other alloys from corrosion and wear,and significantly improving the hardness and wear resistance of the alloys.Firstly,AlSi10Mg alloy used in this work was formed by SLM.And then,a hard ceramic coating is formed on the surface of SLM AlSi10Mg by plasma electrolytic oxidation（PEO）.PEO coatings with different properties were designed for different needs through the optimization of PEO treatment.The micromorphology,phase composition and elemental content of SLM AlSi10Mg and PEO coatings were investigated using field emission transmission electron microscopy（TEM）,Raman spectroscopy,environmental scanning electron microscopy（SEM）and X-ray diffraction spectroscopy（XRD）.The mechanical properties and wear resistance and corrosion resistance of the PEO coatings were analyzed by equipment such as microhardness tester,multifunctional tensile testing machine,electrochemical workstation and dry sliding friction and wear testing machine.The effects of PEO treatment on the microstructure,phase composition,mechanical properties and wear and corrosion resistance of ceramic coatings formed on the surface of SLM AlSi10Mg under different process parameters and conditions were mainly studied.The results show that AlSi10Mg alloy formed by SLM has comprehensive mechanical properties superior to conventional cast AlSi10Mg alloy,such as the ultimate tensile strength of 402MPa,the elongation rate of 9.9%and the hardness of118.7HV0.3.PEO technology is an effective surface protection technology that can provide good protection for SLM AlSi10Mg.After PEO treatment,a hard ceramic coating was formed on the surface of SLM AlSi10Mg alloy.By optimizing the parameters of the PEO process,PEO coatings with the best properties was obtained.Compared to SLM AlSi10Mg,the wear rate and corrosion rate were reduced by 5.7times and 279.3 times,respectively,which means the wear and corrosion resistance of the SLM AlSi10Mg alloy have been significantly improved.The PEO+CNT coatings were prepared by adding carbon nanotube（CNT）to the electrolyte.After the experiments,it was concluded that the PEO coatings formed in the electrolyte with0.1 wt.%CNT addition had the best comprehensive properties.The wear rate(2.30×10-5mm3/N·m)was reduced by one order of magnitude compared to the PEO coatings without CNT addition(1.66×10-4mm3/N·m).The corrosion rate(7.368×10-4mm/a)is slightly higher than that of the PEO coating without CNT addition(6.237×10-5mm/a),but it is still much lower than the corrosion rate of the SLM AlSi10Mg alloy(1.748×10-2mm/a). |
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