脱氢处理对钕镝铁硼磁粉抗氧化性的影响  

Effects of Dehydrogenation on the Oxidation-Resistance of Coarse Nd-Dy-Fe-B Powder

作　　者：谭春林[1] 白书欣[2] 张虹[2] 张家春[1] 蔡珣[1] 

机构地区：[1]上海交通大学材料科学与工程学院,上海200030 [2]国防科技大学航天与材料工程学院,湖南长沙410073

出　　处：《金属热处理》2003年第10期25-28,共4页Heat Treatment of Metals

基　　金：湖南省自然科学基金项目 (0 0JY2 0 4 2 )

摘　　要：研究了氢破碎后经不同温度脱氢处理后Nd Dy Fe B磁粉在室温下不同相对湿度环境中的氧化过程。采用重量法研究磁粉的氧化速率和吸湿率。研究发现 ,未脱氢的磁粉氧化快 ,吸湿率大 ,特别是在氧化的初期 ;而经过脱氢处理后磁粉的抗氧化能力明显提高。对比不同温度脱氢处理的钕氢化物 (NdHx)的氧化结果 ,可以得出 ,脱氢处理后磁粉抗氧化性能提高的机理是氢的析出导致磁粉中的氢化物明显减少甚至消失 ,并使其与大气中水蒸气之间的氢键明显减弱或消失 ,从而降低磁粉的吸湿率 ,抑制了磁粉的电化学腐蚀。而且 ,经脱氢处理后磁粉中的间隙氢原子数量也明显减少 ,氢在磁粉中产生的缺陷相应减少 。This article studied the oxidation of Nd Dy Fe B coarse powder heat treated at different temperature after HD process.The oxidation of powder in different relative humidity was investigated using weight gain method,as well as water absorptance.It was found that the powder without dehydrogenation was oxidized more quickly,and absorbed much more water,especially at the first stage.While the powder with dehydrogenation had higher oxidation resistance because of lower hydrogen concentration and hydrides amount.Comparing them with the oxidation of neodymium hydrides(NdH x ),it was believed that the mechanism of dehydrogenating improving oxidation resistance of Nd Dy Fe B powder after HD probably focus on that hydrogen bonds are broken,which exist between hydrides in the powder and water molecules in air,accelerate the absorption of water from ambient air,and cause the electrochemical reaction in powder more speedily and that less interstitial hydrogen atoms and defects caused by dehydrogenating hinder the diffusion of oxygen atoms.

关 键 词：氢破碎 钕镝铁硼 脱氢处理 抗氧化 吸湿 

分 类 号：TM271[一般工业技术—材料科学与工程]