HFC-227ea／Air气氛对镁合金熔炼保护行为的研究  

Protection Behavior of HFC-227ea/Air Cover Gases to Molten Magnesium Alloy

作　　者：陈晓[1] 杨慧著[1] 

机构地区：[1]福州大学机械工程及自动化学院,福建福州350108

出　　处：《铸造工程》2013年第1期1-5,共5页Foundry Engineering

基　　金：福建省自然科学基金资助项目（2009J01245）

摘　　要：研究了低温室效应的HFC-227ea／Air（空气）对AZ91D镁合金的保护效果。结果表明：以空气为稀释气体时，HFC-227ea能很好地保护镁熔体，其所需的保护气体浓度为0．07％～0．50％。保护效果随着气体浓度的增加、温度的降低而变好。采用SEM、EDS和XRD等分析手段对保护膜进行检测分析可知，保护膜主要由Mg、F和O三种元素组成，其主要物相为MgF2，含有少量的Mg0。保护膜的厚度随着保温时间的延长而增加，保温120min时保护膜厚度约为3．31gm。刚开始形成的保护膜有深色凹陷的MgF2颗粒，随着保温时间的延长，MgF2颗粒不断增加、长大，最终连成片。保护膜主要由MgF2组成，故致密度高，对镁熔体有很好的保护效果。The protective effects of HFC-227ea which has low greenhouse effects on the protection of AZ91D magnesium alloy were studied. The results show that HFC-227ea protective atmospheres with dilution gas of air had perfect protective effects on magnesium. The concentrations that can protect magnesium well are 0.07%-0.50%. The higher the content of protective gas and the lower the melting temperature, the better the protective effect is. The SEM, EDS and XRD were used to analyze the characteristics of the surface film formed in controlled condition. The protective films are composed of F, Mg and O. The composition phases of the protective films are MgF2 and MgO. The oxide film is formed mainly by MgF2 and a little MgO. The protective films get thick with the increase of the holding time, and the thickness is 3.31 gm when the holding time is 120 min. There are many dark concave MgF2 particles in the initial protective films, and the number of MgF2 particles increases with the increase of the holding time. The MgF2 particles grow up at the same time, and finally connect together with each other. Protective film of high density mainly composed of MgF2, and has a perfect protective effect on magnesium. K

关 键 词：镁合金 熔炼 HFC227ea 保护膜 

分 类 号：TG146.2[一般工业技术—材料科学与工程]