Effects of Al coating on corrosion resistance of sintered NdFeB magnet
(1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Hunan Province Key Laboratory of Spray Deposition Technology and Application,
Hunan University, Changsha 410082, China)
2. Hunan Province Key Laboratory of Spray Deposition Technology and Application,
Hunan University, Changsha 410082, China)
Abstract: Pure Al coating was deposited on sintered NdFeB magnet by direct current (DC) magnetron sputtering to improve the corrosion resistance of magnet. The influences of coating thickness and sputtering power on microstructure and corrosion resistance of Al coating were investigated. The surface morphology of Al coating was characterized by scanning electron microscopy (SEM). The corrosion properties were investigated by potentiodynamic polarization curves and neutral salt spray (NSS) test. The formation of the uniform and compact Al coating is a necessary condition to achieve excellent corrosion resistance. And the optimal corrosion resistance can be obtained in the sample with 6.69 μm thick Al coating deposited at 51-82 W.
Key words: NdFeB; aluminum coatings; magnetron sputtering; corrosion resistance; coating thickness