2198铝锂合金稀土铈化学转化膜的制备及耐蚀性研究  

Study on the Preparation and Corrosion Resistance of Cerium-Based Chemical Conversion Coating on 2198 Al-Li Alloy

作　　者：柳绍鑫 王赫男 马雪菲 冯长杰 LIU Shaoxin;WANG Henan;MA Xuefei;FENG Changjie(School of Materials and Engineering,Shenyang Aerospace University,Shenyang 110316,China)

机构地区：[1]沈阳航空航天大学材料科学与工程学院,辽宁沈阳110136

出　　处：《材料保护》2024年第10期134-143,共10页Materials Protection

基　　金：兴辽英才计划项目(XLYC 2002031)。

摘　　要：2198铝锂合金具有较高的比强度及比刚度,在航空航天领域有广泛应用,但其局部腐蚀敏感性较高,需进行适当的表面处理以提高其耐蚀性能。通过化学浸泡法将2198铝锂合金放入0.02 mol/L CeCl_(3)+0.029 mol/L H_(2)O_(2)水溶液中分别处理20、60 min,在其表面获得了稀土化学转化膜。使用扫描电镜(SEM)和能谱仪(EDS)观察和分析了稀土化学转化膜的形貌和成分;用X射线光电子能谱(XPS)分析了转化膜的元素价态;通过测试动电位极化曲线、电化学阻抗能谱(EIS)和Mott-Schottky(M-S)曲线研究了稀土化学转化膜在0.1 mol/L NaCl溶液中的腐蚀行为及耐蚀机制。结果表明:2198铝锂合金稀土化学转化膜由Ce^(4+)和Ce^(3+)的氢氧化物和氧化物、Al^(3+)的氧化物和少量的单质Cu组成,各元素在表面均匀分布;稀土化学转化膜由表面到内部氢氧化物含量减少,氧化物含量增加。处理20 min和60 min获得的稀土化学转化膜的厚度约为0.81μm和1.50μm。在0.1 mol/L NaCl溶液中,稀土化学转化处理能够抑制2198铝锂合金的阴极吸氧过程,降低合金的自腐蚀电流密度,提高合金的耐蚀性;在2198铝锂合金表面制备稀土化学转化膜能使合金的耐蚀性能提高;且与处理20 min的试样相比,处理60 min获得的稀土化学转化膜的耐蚀性较高。同时,稀土化学转化处理改变了合金的腐蚀机制,使与Cl~-吸附相关的感抗弧消失,这是由于具有n型半导体特征的稀土化学转化膜中的载流子密度降低,载流子密度呈现正电荷,不利于Cl~-的吸附。The 2198 aluminum-lithium alloy exhibits a high specific strength and specific stiffness,making it widely applicable in the aero-space sector.However,it is highly sensitive to localized corrosion,necessitating appropriate surface treatments to enhance its corrosion resist-ance.Rare earth chemical conversion coatings on 2198 Al-Li alloy were obtained by immersing the alloy in a solution of 0.02 mol/L CeCl_(3)and 0.029 mol/L H2O2 using chemical immersion method for 20 and 60 min.The morphology and composition of the rare earth chemical conversion coatings were observed and analyzed using scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS).The elemental va-lence states of the conversion coatings were analyzed using X-ray photoelectron spectroscopy(XPS).The corrosion behavior and corrosion re-sistance mechanism of the rare earth chemical conversion coatings in a 0.1 mol/L NaCl solution were studied through potentiodynamic polariza-tion curves,electrochemical impedance spectroscopy(EIS),and Mott-Schottky(M-S)curves.Results showed that the rare earth chemical conversion coating on the 2198 Al-Li alloy was composed of Ce^(4+)and Ce^(3+)hydroxides and oxides,Al3+oxide,and a small amount of Cu ele-ment,with all elements uniformly distributed on the surface.From the surface to the interior of the rare earth chemical conversion coating,the metal hydroxides decreased and the metal oxides increased.The thickness of the rare earth chemical conversion coatings obtained after 20 min and 60 min of immersion was about 0.81μm and 1.50μm,respectively.In the 0.1 mol/L NaCl solution,the rare earth chemical conversion coatings on the 2198 Al-Li alloy could inhibit the cathodic oxygen absorption process,reduce the corrosion current density,and improve the corrosion resistance of this alloy.Compared with the rare earth chemical conversion coating from 20 min of immersion,the coating from 60 min of immersion exhibited higher corrosion resistance.At the same time,the rare earth chemical conversion treatment altered t

关 键 词：2198铝锂合金 氯化铈 稀土化学转化膜 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]