电沉积参数调控对银/石墨烯复合镀层耐腐蚀与耐磨性能的作用OA

To address the thermal damage issues of pure silver coatings caused by their soft texture and poor wear resistance under high temperature or friction conditions,the work aims to propose a method combining graphene doping with electrodeposition technology to construct silver/graphene composite coatings.The regulation mechanism of key process parameters on the structure and performance of the composite coatings was investigated systematically,with the focus on revealing the synergistic enhancement mechanism of their corrosion resistance and wear resistance,and composite coatings with excellent corrosion and wear resistance were prepared. Silver cyanide(AgCN)was selected as the main metal salt in the electrolyte because it formed a stable[Ag(CN)2]-complex to ensure stable Ag+release during the electrodeposition process.Graphene was added as a second phase to the AgCN-based solution to prepare a silver/graphene composite electroplating system.Single-factor experiments were innovatively combined with multi-parameter interaction analysis.Firstly,through single-factor experiments,the independent effects of graphene concentration(0.1-0.8 g/L),stirring speed(100-600 r/min),and current density(0.5-4 A/dm2)on the coating performance were investigated separately.With scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),corrosion resistance(measured by potentiodynamic polarization in 3.5wt.%NaCl),and wear resistance(measured by ball-on-disc friction)as evaluation criteria,the microstructure,elemental composition,corrosion resistance,and wear resistance of the coatings were characterized,and the optimal parameter window was preliminarily determined.On this basis,fractional factorial design and response surface methodology(RSM)were further employed to systematically analyze the interactions among multiple process parameters and their synergistic effects on the performance of the composite coatings,thereby establishing a quantitative relationship between process-structure-performance and determining the globally optimal process conditions. The results of the single-factor experiments indicated that there were optimal process conditions within the ranges of graphene concentration from 0.1 to 0.8 g/L,stirring speed from 100 to 600 r/min,and current density from 0.5 to 4 A/dm2.These parameters all affected the carbon content and microstructure of the composite coatings,thereby affecting their corrosion resistance and wear resistance.For example,insufficient graphene(<0.2 g/L)could not effectively enhance the coating,while excessive graphene(>0.8 g/L)could lead to agglomeration.Statistical analysis revealed significant parameter interactions,with the effect strength on corrosion and wear resistance being in the order of graphene concentration>stirring speed>current density.The results of fractional factorial design combined with response surface methodology indicated that the effects of three process parameters on the corrosion resistance and wear resistance of silver/graphene composite coatings were interactive.Response surface analysis showed that there was a significant interaction effect among the three parameters,with graphene concentration having the most significant impact on both corrosion resistance and wear resistance,followed by stirring speed,and current density having a relatively weaker impact. This study identified the optimal preparation window for silver/graphene composite coatings through multi-scale process regulation and mechanism analysis:graphene concentration of 0.2-0.5 g/L,current density of 1-2.8 A/dm2,and stirring speed of 200-350 r/min.The composite coating exhibited excellent comprehensive performance under the combined effects of wear and corrosion,and its strengthening mechanism was mainly attributed to the grain refinement,shielding effect,and tribological modification caused by the incorporation of graphene.This study provides reliable experimental and theoretical support for the development of high-performance silver-based composite protective coatings.