磷化温度对烧结Nd-Fe-B永磁合金表面磷酸盐化学转化膜组织结构和耐蚀性能的影响  

Influence of Phosphating Temperature on Microstructure and Corrosion Resistance of Phosphate Chemical Conversion Coating on Sintered Nd-Fe-B Permanent Magnets

作　　者：丁霞 Ding Xia(School of Intelligent Engineering,Shandong Management University,Jinan 250357,China)

机构地区：[1]山东管理学院智能工程学院,山东济南250357

出　　处：《稀有金属材料与工程》2022年第5期1627-1636,共10页Rare Metal Materials and Engineering

基　　金：Shandong Provincial Natural Science Foundation,China(ZR2019BEM014);Doctoral Scientific Research Foundation of Shandong Management University(SDMUD201719)。

摘　　要：研究了磷化温度对烧结钕铁硼永磁合金表面磷酸盐化学转化(PCC)膜的形成、微观结构和耐蚀性能以及对磁体磁性能的影响。结果表明,随着磷化温度的升高,转化膜膜重略有增加。扫描电镜观察结果表明,转化膜呈块状结构,晶粒尺寸为5~10μm。能量色散谱和傅里叶变换红外光谱测试表明,转化膜主要由钕磷酸盐水合物、镨磷酸盐水合物和少量铁磷酸盐水合物组成。转化膜中的氧、磷元素主要分布在晶粒表面,铁元素主要集中在晶界处,钕和镨的分布则比较均匀。电化学分析和静态全浸腐蚀试验表明,不同温度下制备的转化膜均可以提高烧结钕铁硼永磁合金的耐蚀性能。在70℃下制备的转化膜由于组织结构均匀致密,具有更好的耐蚀性能。磷化处理后,样品的磁性能均有所下降,但是70℃下处理的样品性能相对较好。因此,烧结Nd-Fe-B永磁合金的最佳磷化温度为70℃。The effect of phosphating temperature on formation,microstructure,and corrosion resistance of the phosphate chemical conversion(PCC)coatings and that on the magnetic property of the sintered Nd-Fe-B permanent magnets were investigated.The results show that the coating mass is increased slightly with increasing the phosphating temperature.The scanning electron microscope observation demonstrates that PCC coatings have blocky structure with the grain size of 5~10μm.The analyses of energy dispersive spectra and Fourier transform infrared spectrometer spectra reveal that the coatings are mainly composed of neodymium phosphate hydrate,praseodymium phosphate hydrate,and a small amount of iron phosphate hydrate.The oxygen and phosphorous elements in PCC coatings are mainly distributed on the grain surface,while the iron element is mainly concentrated at the grain boundaries.The distribution of neodymium and praseodymium is relatively uniform.The electrochemical analysis and static immersion corrosion test show that PCC coatings prepared at different temperatures can effectively improve the corrosion resistance of the sintered Nd-Fe-B permanent magnets.The coatings prepared at 70℃exhibit a better corrosion resistance due to the uniform and dense microstructure.Although the magnetic properties of the sintered Nd-Fe-B permanent magnets with PCC coatings are decreased,those with PCC coatings prepared at 70℃ are relatively fine.The optimal phosphating temperature of 70℃ for the sintered Nd-Fe-B permanent magnets is determined.

关 键 词：钕铁硼永磁合金 磷酸盐化学转化 磷化温度 组织结构 耐蚀性能 磁性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]