【作者】 王伟；

【导师】 赵景茂； 黄先球；

【作者基本信息】 北京化工大学 ， 材料工程（专业学位）， 2020， 硕士

【摘要】 微弧氧化处理有利于增强材料的耐蚀性,但由于微弧氧化成膜的特点导致制备的膜层存在大量放电孔洞,这为腐蚀介质的侵入提供了便利,因此有必要研究微弧氧化工艺和膜层封孔技术,通过减少膜层孔洞来进一步提高材料的耐蚀性。目前关于工艺参数对钛合金微弧氧化膜层结构与性能的影响规律还不够全面,而且国内外关于钛合金微弧氧化膜层封孔技术的研究多是结合磁控溅射等复杂工艺,为解决该问题,本文选用TC4钛合金,通过电化学阻抗谱、动电位极化曲线、接触角测试、XRD、SEM/EDS和红外光谱等手段,详细研究了微弧氧化工艺参数对膜层结构与耐蚀性的影响规律以及采用硬脂酸和BTESPT硅烷这两类工艺简单的封孔处理后膜层结构和性能的变化。研究结果表明膜层的耐蚀性能与膜层表面孔隙率密切相关,适当增加脉冲频率,减小电流密度和占空比并选择合适的氧化时间能制备出表面孔隙率更小的微弧氧化膜层,从而达到改善膜层耐蚀性的目的。采用硬脂酸或BTESPT硅烷对膜层进行封孔处理后,都能有效地封闭膜层的孔洞,并提高膜层表面的疏水性。与未处理的微弧氧化膜层相比,经硬脂酸封孔处理或硅烷封孔处理后的膜层均显示出更低的腐蚀电流密度和更高的阻抗值,膜层耐蚀性明显提高,表明硬脂酸处理和硅烷处理均是行之有效的表面处理手段,工艺简单且效果明显,为简化微弧氧化膜层封孔工艺提供了思路,有利于拓宽微弧氧化技术的应用范围。更多还原

【Abstract】 Micro-arc oxidation treatment is beneficial to enhance the corrosion resistance of the material.However,due to the characteristics of micro-arc oxidation coating formation,there are a large number of discharge holes appearing in the prepared coating,which provides convenience for the invasion of corrosive media.Therefore,it is necessary to study the micro-arc oxidation process and film sealing technology to further improve the corrosion resistance of the material by reducing the coating holes.At present,the influence of process parameters on the structure and performance of titanium alloy micro-arc oxide coating is not comprehensive enough,and the domestic and foreign researches on the sealing technology of titanium alloy micro-arc oxidation coating are mostly combined with complex processes,such as magnetron sputtering.In order to solve this problem,TC4 titanium alloy was selected in this paper.By the means of electrochemical impedance spectroscopy,dynamic potential polarization curve,contact angle test,XRD,SEM/EDS and infrared spectroscopy,the effect of micro-arc oxidation process parameters on the coating structure and corrosion resistance was studied in detail,and the changes in coating structure and properties were studied after sealing by two simple processes with stearic acid and BTESPT silane either.The results show that the corrosion resistance of the coating is closely related to the surface porosity of the coating.To achieve the purpose of improving the corrosion resistance of coating,increasing the pulse frequency properly,reducing the current density and duty cycle,and selecting the appropriate oxidation time are beneficial to the preparation of micro-arc oxidation coating with a smaller surface porosity.After sealing by stearic acid or BTESPT silane,the pores of the coating can be effectively closed,and the hydrophobicity of the coating surface can be improved.Compared with the untreated micro-arc oxidation coating,the coating after stearic acid or silane sealing treatment showed lower corrosion current density and higher resistance value,and the corrosion resistance of the coating was obviously improved.The result indicates that both stearic acid treatment and silane treatment are effective surface treatment methods,process is simple and the effect is obvious.It provides an idea for simplifying the micro-arc oxidation film sealing process and is beneficial to broadening the application range of micro-arc oxidation technology.更多还原