CAJ | 학술논문

基于原位腐蚀观察方法,采用光学显微镜(OM)、扫描电镜(SEM)和能谱分析(EDS)、盐水浸泡实验等研究 Mg-Gd-Y-Nd-Zr 合金在3.5%NaCl(质量分数)溶液中的腐蚀机理,探讨不同第二相在合金局部腐蚀中的作用机制.结果表明,合金腐蚀初期表现出典型的点蚀特征,富Gd和富Y粒子作为阴极相导致边缘基体相α-Mg的优先溶解,富Zr粒子中的Mg和边缘α-Mg都优先发生腐蚀,且腐蚀源的具体位置与第二相粒子和基体表面间的方位有关.在局部腐蚀过程中,具有更高稀土或锆含量的第二相微区表现出更好的耐蚀性能.此外,在第二相密集分布的区域,第二相粒子充当腐蚀屏障,使微区的耐蚀性能提高.
기우원위부식관찰방법,채용광학현미경(OM)、소묘전경(SEM)화능보분석(EDS)、염수침포실험등연구 Mg-Gd-Y-Nd-Zr 합금재3.5%NaCl(질량분수)용액중적부식궤리,탐토불동제이상재합금국부부식중적작용궤제.결과표명,합금부식초기표현출전형적점식특정,부Gd화부Y입자작위음겁상도치변연기체상α-Mg적우선용해,부Zr입자중적Mg화변연α-Mg도우선발생부식,차부식원적구체위치여제이상입자화기체표면간적방위유관.재국부부식과정중,구유경고희토혹고함량적제이상미구표현출경호적내식성능.차외,재제이상밀집분포적구역,제이상입자충당부식병장,사미구적내식성능제고.
@@@@Based on in-situ corrosion observation, the corrosion mechanism of Mg-Gd-Y-Nd-Zr alloy in 3.5% NaCl (mass fraction) solution was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and saline immersion test. The action mechanism of various second phase particles on localized corrosion of the alloy was also studied. The results show that pitting is the typical and obvious feature in the initial stage of corrosion. Gd-rich and Y-rich particles promote corrosion ofα-Mg as cathode of corrosion galvanic cell, while both Mg in Zr-rich particle andα-Mg close to Zr-rich phase corrode preferentially. Moreover, the exact location of corrosion is concerned with the orientation between the second phase particle and the matrix. In the process of localized corrosion, the second phase with higher content of RE elements or Zr shows better corrosion resistance. Furthermore, the area distributed with intensive second phase particles exhibits better corrosion resistance, which is ascribed to the barrier effect derived from the interaction between particles.