CAJ | 학술논문

通过现场暴露实验,研究了AZ31镁合金在西沙海洋大气环境下暴露4 a的长周期腐蚀行为.利用扫描电镜观察表面、截面的腐蚀产物以及去除腐蚀产物后的腐蚀形貌,并用能谱分析及X射线衍射仪对腐蚀产物的元素含量及相组成进行分析.研究结果表明,AZ31镁合金在西沙海洋大气环境下发生了较为严重的腐蚀,4 a内的平均腐蚀速度为11.95μm·a-1. Cl-和CO2在镁合金的腐蚀过程中起着至关重要的作用.吸附液膜中的Cl-主要破坏镁合金的保护膜,使镁合金发生阳极溶解；而CO2则会中和阴极反应产生的碱性离子并与Mg(OH)2发生反应生成含不同结晶水的Mg5(CO3)4(OH)2·xH2O表层腐蚀产物.由于表层腐蚀产物阻挡了CO2和Cl-向镁合金表面的传输,靠近基体处的腐蚀产物主要为Mg( OH)2.
통과현장폭로실험,연구료AZ31미합금재서사해양대기배경하폭로4 a적장주기부식행위.이용소묘전경관찰표면、절면적부식산물이급거제부식산물후적부식형모,병용능보분석급X사선연사의대부식산물적원소함량급상조성진행분석.연구결과표명,AZ31미합금재서사해양대기배경하발생료교위엄중적부식,4 a내적평균부식속도위11.95μm·a-1. Cl-화CO2재미합금적부식과정중기착지관중요적작용.흡부액막중적Cl-주요파배미합금적보호막,사미합금발생양겁용해；이CO2칙회중화음겁반응산생적감성리자병여Mg(OH)2발생반응생성함불동결정수적Mg5(CO3)4(OH)2·xH2O표층부식산물.유우표층부식산물조당료CO2화Cl-향미합금표면적전수,고근기체처적부식산물주요위Mg( OH)2.
By field exposure test, atmospheric corrosion tests of AZ31 magnesium alloy were conducted in Xisha Islands for 4 a. The surface and cross-section morphologies of corrosion products as well as the corrosion morphologies of the alloy after removing corro-sion products were observed by scanning electron microscopy. Energy dispersive X-ray spectroscopy and X-ray diffraction analysis were used to obtain the element content and phase composition of corrosion products. The results indicate that the alloy undergoes severe corrosion. The average corrosion rate is 11.95μm·a-1 . Cl-and CO2 play important roles in the corrosion process. The Cl--containing absorbed electrolyte layers will destroy the oxidation film and induce anodic dissolution of the alloy. While CO2 dissolved in the absorbed electrolyte layers tends to neutralize the alkali formed in the cathodic area and reacts with Mg ( OH ) 2 to form Mg5 ( CO3 ) 4 ( OH) 2·xH2 O. The surface corrosion products restrict the transport of CO2 and Cl- to the surface of the alloy, so the inner layer of corrosion products is mainly composed of Mg( OH) 2 .