CAJ | 학술논문

800合金作为核电站蒸汽发生器的一种关键材料,服役环境下其表面钝化膜的特性一直是人们研究的热点。本文用Mott-Schottky方法研究了800合金在不同硫酸根离子和氯离子浓度比的溶液中钝化膜的半导体特性,并结合电化学阻抗谱(EIS)、扫描电镜(SEM)、扫描电化学显微镜(SECM)研究了钝化膜的耐蚀性和表面活性。 Mott-Schottky结果表明,800合金表面钝化膜的半导体特性与溶液中硫酸根、氯离子的浓度比有关,随硫酸根与氯离子浓度比的降低,半导体特性发生转变。当硫酸根与氯离子的浓度比较高时,钝化膜为p型半导体；而当硫酸根与氯离子的浓度比较低时,钝化膜为n型半导体。 EIS、SECM、SEM结果表明,随浓度比的降低钝化膜由过钝化溶解转为明显的点蚀特征,钝化膜表面活性增加。钝化膜特性的改变与其半导体类型的转变密切相关,而半导体特性的转变由氯离子、硫酸根离子在800合金钝化膜表面的竞争吸附所致,其在表面的竞争吸附直接影响钝化膜表面发生的化学反应,改变电极/溶液界面电势差,使钝化膜中的空位类型改变,最终决定半导体类型。
800합금작위핵전참증기발생기적일충관건재료,복역배경하기표면둔화막적특성일직시인문연구적열점。본문용Mott-Schottky방법연구료800합금재불동류산근리자화록리자농도비적용액중둔화막적반도체특성,병결합전화학조항보(EIS)、소묘전경(SEM)、소묘전화학현미경(SECM)연구료둔화막적내식성화표면활성。 Mott-Schottky결과표명,800합금표면둔화막적반도체특성여용액중류산근、록리자적농도비유관,수류산근여록리자농도비적강저,반도체특성발생전변。당류산근여록리자적농도비교고시,둔화막위p형반도체；이당류산근여록리자적농도비교저시,둔화막위n형반도체。 EIS、SECM、SEM결과표명,수농도비적강저둔화막유과둔화용해전위명현적점식특정,둔화막표면활성증가。둔화막특성적개변여기반도체류형적전변밀절상관,이반도체특성적전변유록리자、류산근리자재800합금둔화막표면적경쟁흡부소치,기재표면적경쟁흡부직접영향둔화막표면발생적화학반응,개변전겁/용액계면전세차,사둔화막중적공위류형개변,최종결정반도체류형。
Al oy 800 is an important steam generator material used in nuclear power plants, and so there is significant interest in the properties of passive films of this alloy under service conditions. In this work, the semiconductivity of Al oy 800 in sulfate and chloride solutions was investigated using Mott-Schottky analysis, electrochemistry impedance spectroscopy (EIS), scanning electron microscopy (SEM), and scanning electrochemical microscopy (SECM). The Mott-Schottky results show that the semiconductivity is affected by the sulfate to chloride concentration ratio;p-type semiconductivity is exhibited at high concentration ratios but transitions to n-type when the concentration ratio is low. EIS, SEM, and SECM results indicate that the degradation form of the passive film changes from transpassive dissolution to pitting as the concentration ratio decreases while the film′s surface reactivity increases, an effect that is related to the semiconductivity conversion. The observed variation in semiconductivity results from the competitive adsorption of sulfate and chloride, a process that modifies the potential drop at the film/solution interface, changes the vacancy types and ultimately determines the semiconductivity.