On The Protection To The NdFeB Permanent Magnet By The Cathotic Electrophoretic Paint Of The Bisphenol-A Epoxy Resin

The NdFeB permanent appeared as the third-generation permanent material which has excellent magnetic performance and has been applied in the fields of environment protection, medical treatment, mining, electron information system and national defence, etc. It plays an important role in the national economy. But the rich- Nd in the NdFeB is easily oxidized in the air especially in the moist air which brings about magnet pulverization, magnetic performance decreasing, thus influencing the normal run of instruments, shorting the using life of the NdFeB permanent magnet, limiting the scope of the NdFeB. So it is a key problem to improve the anticorrosion of the NdFeB. In this paper, in order to improve the anticorrosion and accelerate the further applying of the NdFeB, based on production of predecessors and many references, the protecting performance of NdFeB has been developed by using the cathotic electrophoretic paint of Bisphnol-A epoxy resin.(1) The phosphating technics on the NdFeB surface before the deposition of the cathotic electrophoretic paint and the mechanism of the phosphating film on the NdFeB were carried through. The phosphating technics of good performance phosphating film was confirmed which established the ideal foundation for the deposition of the cathotic electrophoretic paint and the phosphating film mechanism of the Zn-phosphating solution on the NdFeB was brought forward. The phosphating disposal of the NdFeB was done by two different phosphating technics, Ti-adjuster (self-preparation) plus Zn-phosphating solution (self-preparation) and usual organic acid adjuster plus Zn-phosphating solution (self-preparation). The micrograph of samples have been observed by SEM, the anticorrosion performance of the phosphating film was measured by the CuSO4 dropping method (GB6807-86), the composition and the consisting element of the phosphating film were analyzed by the XRD and the EDS, the Nd-element in the phosphating solution was qualitatively analyzed by the ICP-AES before and after phosphating. The results show that the compact and even phosphating film with strong anticorrosion is obtained on the...