Method for preparation of a sintered type NdFeB permanent magnet with an adjusted grain boundary

摘要

The disclosure relates to a method for preparing sintered type NdFeB permanent magnet. The NdFeB magnet is covered with a diffusion source to form a NdFeB magnet intermediate. The diffusion source refers to an alloy, the alloying elements include one or more of Nd, Pr, Ce, La, Ho, Tb, Dy, Ga, Al, Cu, and Mg. The NdFeB magnet intermediate is then put into a furnace and a diffusion treatment and subsequently an aging treatment is performed. The aging treatment is divided into a heating step and a cooling step. The cooling step is carried out by means of argon gas positive pressure circulation cooling such that NdFeB magnets with a thickness of grain boundaries in the range of 10 nm to 1 μm are formed.