2198铝锂合金稀土铈化学转化膜的制备及耐蚀性研究

柳绍鑫, 王赫男, 马雪菲, 冯长杰

doi:10.16577/j.issn.1001-1560.2024.0233

材料保护 >

2024 , Vol. 57 >Issue 10: 134 - 143

DOI: https://doi.org/10.16577/j.issn.1001-1560.2024.0233

工艺篇

2198铝锂合金稀土铈化学转化膜的制备及耐蚀性研究

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沈阳航空航天大学材料科学与工程学院

冯长杰(1977-)，教授，博士，主要研究方向为新型环保电镀镀层及其槽液离子分析，电话:13066635385，E-mail:chjfengniat＠126.com

收稿日期: 2024-03-19

修回日期: 2024-04-10

录用日期: 2024-04-11

网络出版日期: 2024-12-22

基金资助

兴辽英才计划项目(XLYC 2002031)

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

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(School of Materials and Engineering， Shenyang Aerospace University， Shenyang 110316， China)

FENG Changjie(1977-)， Professor， Ph.D.， Research Focus: New Environmentally Friendly Electroplating Coatings and Its Solution Ion Analysis， Tel.: 13066635385， E-mail: chjfengniat＠126.com

Received date: 2024-03-19

Revised date: 2024-04-10

Accepted date: 2024-04-11

Online published: 2024-12-22

Supported by

The Liaoning Revitalization Talents Program (XLYC 2002031)

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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 CeCl3＋0.029 mol/L H2O2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Ce4＋和Ce3＋的氢氧化物和氧化物、Al3＋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0.81 μm 和1.50 μm。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。

关键词： 2198 铝锂合金; 氯化铈; 稀土化学转化膜; 耐蚀性

本文引用格式

柳绍鑫, 王赫男, 马雪菲, 冯长杰 . 2198铝锂合金稀土铈化学转化膜的制备及耐蚀性研究[J]. 材料保护, 2024 , 57(10) : 134 -143 . DOI: 10.16577/j.issn.1001-1560.2024.0233

Abstract

The 2198 aluminum-lithium alloy exhibits a high specific strength and specific stiffness， making it widely applicable in the aerospace sector.However， it is highly sensitive to localized corrosion， necessitating appropriate surface treatments to enhance its corrosion resistance.Rare earth chemical conversion coatings on 2198 Al-Li alloy were obtained by immersing the alloy in a solution of 0.02 mol/L CeCl3 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 valence states of the conversion coatings were analyzed using X-ray photoelectron spectroscopy (XPS).The corrosion behavior and corrosion resistance mechanism of the rare earth chemical conversion coatings in a 0.1 mol/L NaCl solution were studied through potentiodynamic polarization 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 Ce4＋and Ce3＋hydroxides and oxides， Al3＋oxide， and a small amount of Cu element， 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 0.81 μm and 1.50 μm， 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 the corrosion mechanism of the alloy，resulting in the disappearance of the impedance arc related to Cl- adsorption.This was attributed to the reduced carrier density in the rare earth chemical conversion coating，which exhibited n-type semiconductor characteristics；the positive charge of the carrier density hindered the adsorption of Cl-.

Key words： 2198 Al-Li alloy; cerium chloride; rare earth chemical conversion film; corrosion resistance

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