Changes of Magnetic Properties and Microstructure of NdFeB Ternary System Alloys during Annealing Process

Under temperatures (773~1023K), the results show that in early stage of annealing the coercivity increases sharply and after a peak value, it decrease again. The coercivity for the specimens under annealing state was enhanced one time compared with that of the sintered state. The matrix phase was single phase, in which no crystalline defect was found and the matrix phase was unchanged, only the grain boundaries change. The increase of the coercivity ofter annealing was connected with the changes of grain boundaries.