占空比对SiCp/Al基复合材料微弧氧化膜层组织及性能的影响

Effects of Duty Cycles on Microstructure and Properties of Micro⁃Arc Oxidation Films Prepared on SiCp/Al Based Composite Materials

以NaAlO2+NaOH为电解液体系,在恒压模式下对SiC体积分数为45%,粒径为5μm的SiCp/Al基复合材料表面进行微弧氧化处理,研究了占空比对SiCp/Al基复合材料微弧氧化膜层组织及性能的影响。用SEM分析微弧氧化膜层的形貌;用X射线衍射仪分析膜层的相组成;采用粗糙度仪、维氏硬度仪、划痕仪对膜层粗糙度、显微硬度及结合力进行了分析;用电化学工作站分析膜层的耐蚀性。结果表明:随着占空比的增大,微弧氧化膜层变得连续,厚度呈现增加趋势,粗糙度逐渐增加,孔隙率逐渐降低。占空比对微弧氧化膜层的物相有一定影响。SiCp/Al基复合材料微弧氧化膜层与基体的结合力随占空比的增加先增大后减小。不同占空比下制备的微弧氧化膜层均能提高SiCp/Al基复合材料的耐蚀性,占空比为70%时制备的微弧氧化膜层耐蚀性最好。

Using NaAlO2+NaOH as the electrolyte system,under constant pressure mode,the volume fraction of SiC was 45%,and the parti⁃cle size was 5μm,the surface of SiCp/Al based composite material was subjected to micro⁃arc oxidation treatment,and the effect of duty cycle on the microstructure and properties of the micro⁃arc oxidation film of SiCp/Al based composite material was studied.SEM was used to analyze the morphology of micro⁃arc oxidation film under different duty cycles.The phase composition of the film was studied by X⁃ray diffractometry.The roughness,micro⁃hardness and bonding force of the film were analyzed by roughness meter,Vickers hardness tester and scratch meter.The corrosion resistance of the film was studied by electrochemical workstation.Results showed that with the increase of duty cycle,the micro⁃arc oxidation film became continuous,the thickness showed an increasing trend,the roughness gradually increased,and the porosity gradually de⁃creased.The duty cycle had a certain effect on the phase composition of micro⁃arc oxidation film.The adhesion between the micro⁃arc oxidation film and the substrate of SiCp/Al based composite materials first increased and then decreased with the increase of the duty cycle.The micro⁃arc oxidation film prepared under different duty cycles all improved the corrosion resistance of SiCp/Al based composite materials.The corrosion resistance of SiCp/Al based composite materials was the best when the duty cycle was 70%.