脉冲频率对机载设备铝合金微弧氧化膜的影响

Influence of Pulse Frequency on Aluminum Alloy Micro-Arc Oxidation Film of Airborne Equipment

选用复合电解液体系和双极性脉冲电源,在脉冲频率分别为250 Hz、500 Hz和750 Hz条件下制备出2024机载设备铝合金微弧氧化陶瓷膜。使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、涡流涂层测厚仪、粗糙度检测仪、维氏硬度计、附着力测试仪和电化学工作站分别对微弧氧化膜层的微观形貌、元素组成、相结构、厚度、粗糙度、硬度、油漆附着力和耐蚀性进行测试分析。结果表明,膜层元素组成为Al、O、C、P、Si、W、Na,其中,Al和O为主要元素,膜层相结构主要组成为α-Al_(2)O_(3)和γ-Al_(2)O_(3),250 Hz时衍射峰最为明显。随着脉冲频率的增加,膜层微观表面的孔洞明显变小且膜层更细腻,膜层的厚度、粗糙度、硬度和油漆附着力都随着频率的增加而减小。电化学测试结果表明,500 Hz时的膜层耐蚀性最好,750 Hz时耐蚀性最差。

Using a composite electrolyte system and bipolar pulse power supply,the 2024 airborne equipment aluminum alloy micro-arc oxidation ceramic film are prepared under the conditions of pulse frequency of 250 Hz,500 Hz and 750 Hz Using SEM,XRD,coating thickness gauge,roughness tester,Vickers hardness tester,adhesion tester and electrochemical workstation,the micromorphology,elemental composition,phase structure,thickness,roughness hardness,paint adhesion and corrosion resistance of the micro-arc oxidation film are investigated respectively.The results show that the elemental composition of the film is Al,O,C,P,Si,W and Na,among which Al and O are the main elements,the main composition of the film phase structure is α-Al_(2)O_(3) and γ-Al_(2)O_(3),and the diffraction peak at 250 Hz is the most obvious.With the increase of the pulse frequency,the pores on the microscopic surface of the film layer are obviously smaller and the film layer is more delicate.The film thickness,roughness,hardness and paint adhesion all decrease with the increase of frequency.Electrochemical tests show that the coating has the best corrosion resistance at 500 Hz and the worst corrosion resistance at 750 Hz.