Effects of annealing process on magnetic properties and structures of Nd–Pr–Ce–Fe–B melt-spun powders

•The slow cooling rate help to improve magnetic properties for high Ce-content powders.•The optimal annealing temperature is 590–650 °C when annealing time is fixed in 5 min.•The powders will contain Fe2B and α-Fe when the annealing time is more than 3 min.•The oxygen contents of powders change little after low temperature or short time annealed.

The effects of annealing process on magnetic properties and structures of Nd–Pr–Ce–Fe–B melt-spun powders have been investigated. The magnetic properties improve a lot when the annealing temperature is 590–650 °C and the annealing time exceeds 1 min. The magnetic properties is stable when the annealing time is 590–650 °C. The powders contains obvious grains when the annealing time is only 1 min, while the grains grow up obviously, leading to the decrease of Br and (BH)max, when the annealing time is more than 9 min. The Hcj changes little for different annealing time. The cooling rate also affects the magnetic properties of powders with different Ce-content. Faster cooling rate is favorable to improve magnetic properties with low Ce-content powders, while high Ce-content powders need slower cooling rate.