终电压对铝合金Mo和V黑色微弧氧化膜形成过程的影响  

Influence of Final Voltage on Formation Process of Black Micro-arc Oxidation Coating on Aluminum Alloy with Mo and V

作　　者：刘圆敬 刘丹 单大勇 韩恩厚 LIU Yuanjing;LIU Dan;SHAN Dayong;HAN Enhou(Institute of Corrosion Science and Technology,Guangzhou 510530,China)

机构地区：[1]广东腐蚀科学与技术创新研究院,广州510530

出　　处：《表面技术》2024年第9期34-42,共9页Surface Technology

基　　金：广州市基础研究计划(SL2022A04J00598)。

摘　　要：目的以钼酸盐和钒酸盐为着色剂,探究终电压对黑色微弧氧化膜形成过程的影响。方法在六偏磷酸钠和硅酸钠的微弧氧化体系中,添加NH4VO_(3)和Na2MoO4作为着色剂,在清洁的6063铝合金表面获得不同终电压下的微弧氧化膜,通过SEM、XRD、XPS分析膜层的形貌、结构和成分,通过色差仪和紫外可见分光光度计表征膜层的颜色特性和吸光率,通过极化曲线和电化学阻抗谱分析膜层的电化学性能。结果膜层的主要成分为O、Al、P、Si、Mo、V,其中Mo、V以MoO_(3)、MoO_(2)、V_(2)O_(5)、V_(2)O_(3)的形式存在。当终电压从350 V提高至550 V时,微弧氧化膜层的微孔变得少而大,颜色由褐色逐渐变为黑色,L从65.01减小到22.63,对可见光(波长250~800 nm)的吸收率从69.4%增至96.5%以上,膜层厚度和粗糙度从4.00、0.55μm分别增至35.00、2.41μm,自腐蚀电流密度降至1.48×10^(−6) A/cm^(2),自腐蚀电位(vs.SCE)正移至−0.07 V,阻抗值大幅提高,达到2.48×10^(5)Ω·cm^(2)。结论NH_(4)VO_(3)、Na2MoO4是铝合金黑色微弧氧化的有效着色剂,反应生成的V_(2)O_(5)、V_(2)O_(3)、MoO_(3)、MoO_(2)是膜层呈现黑色的根本原因,随着终电压的升高,膜层吸光率和耐蚀性均提高,氧化膜的完整性对膜层性能的影响显著。NH_(4)VO_(3) and Na_(2)MoO_(4) were chosen as colorants to investigate the influence of different final voltages on properties of black micro-arc oxidation coatings on aluminum alloys,and the formation process of the coatings.In the micro-arc oxidation system of sodium hexametaphosphate and sodium silicate,NH_(4)VO_(3) and Na_(2)MoO_(4) were added as colorants to obtain micro-arc oxidation films on the clean surface of 6063 aluminum alloy at different final voltages(350,400,450,500,550 V),with micro-arc oxidation electrical parameters set as constant current mode,with a current density of 10 A/dm^(2),frequency of 800 Hz,and a duty cycle of 10%.The morphology,structure,and composition of the coatings were analyzed by SEM,XRD,and XPS.The roughness and thickness of micro-arc oxidation coatings were conducted with a white light interferometer and a thickness gauge.The color characteristics and absorbance of the coatings were characterized with a colorimeter and a UV-visible spectrophotometer,and the electrochemical properties of the coatings were analyzed by polarization curves and electrochemical impedance spectroscopy.The crystallinity of the micro-arc oxidation coating was relatively low.The main components of the coating were O,Al,P,Si,Mo and V,with Mo and V existed as MoO_(3),MoO_(2),V_(2)O_(5) and V_(2)O_(3).The micro-arc oxidation coatings at different final voltage tightly bonded with the substrate,there were no obvious cracks between the coating and the substrate.As the final voltage increased from 350 V to 550 V,the micro-arc oxidation coating underwent remelting,the surface discharge channels on the coating transited from small and dense to large and sparse.And the average pore size increased from(0.82±0.64)μm to(2.58±1.8)μm.The color of the micro-arc oxidation coatings changed gradually from brown to black,the L value decreased from 65.01 to 22.63,the light absorption for visible light(wavelength 250-800 nm)increased from 69.4%to over 96.5%.The thickness and roughness of the coatings increased from 4.

关 键 词：铝合金 黑色微弧氧化 耐蚀性 着色机理 吸光率 电化学 

分 类 号：TG178[金属学及工艺—金属表面处理]