Increasing the Coercivity of (Nd,Pr)–(Fe,Co,Cu,Al,Ga)–B Magnets without Adding Heavy Rare Earth Elements

The effect of various heat treatments on the magnetic properties and microstructure of magnets manufactured using low-oxygen technology from the (Nd,Pr)31.9Febal.(Co,Cu,Al,Ga)1.7B0.8 (wt %) alloy has been studied. It has been shown that the two-stage heat treatment leads to a significant increase in the coercive force of the magnets compared to the single-stage one. The obtained magnets have the properties (Br = 13.2 kG, MHc = 17.9 kOe, BHc = 12.5 kOe, (BH)max = 42.4 MG Oe, α = –0.11%/ºС, β = –0.54%/°С) corresponding to the properties of (Nd,Dy)–Fe–B magnets used to produce magnetic systems of wind turbines. The use of Pr and Ga makes it possible to reduce the cost of the initial alloy compared to alloys with Dy.