Phase-structural state diagrams and hysteresis properties of rapidly solidified alloy Nd10.4Zr4.0Fe75.1Co4.1B6.4 after heat treatment

This paper investigates complex studies of phase composition, thin crystalline structure parameters and magnetic properties of rapidly solidified alloy powders Nd10.4Zr4.0Fe75.1Co4.1B6.4 in initial state and after heat treatments in the temperature range 380-700 °C for 30, 60 and 120 min. The research shows that there is a hard magnetic phase Nd2Fe14B and soft magnetic phases α-Fe and Nd2Fe17 in the structure of the investigated as-solidified alloy. And low-magnetic properties (Hci = 186 kA/m) are due to the presence of the Nd2Fe17 phase. After heat treatments in the temperature range 520-550 °C coercivity of the powders grow up to Hci ≈ 750 kA/m. However, after annealing at the temperatures higher than 600 °C, coercivity drastically drops due to the phase transformation of a hard magnetic phase Nd2Fe14B and the average grain growth, with the phase transforming into a soft magnetic phase Nd2Fe17.