Auxiliary alloy casting piece, high-residual-magnetism high-coercivity neodymium-iron-boron permanent magnet and preparation method

The invention provides an auxiliary alloy casting piece, a high-residual-magnetism and high-coercivity neodymium-iron-boron permanent magnet and a preparation method, and belongs to the technical field of permanent magnets. The preparation method of the auxiliary alloy casting piece comprises the following steps that auxiliary alloy raw materials are provided, and the auxiliary alloy raw materials comprise, by mass, 40%-45% of Pr, 1%-2% of Co, 0.5%-1% of Ga, 0.6%-0.8% of B, 0.1%-0.2% of V, 0.3%-0.7% of Ti and the balance Fe; the auxiliary alloy raw material is smelted, and a smelted material is obtained; the smelted material is subjected to rapid hardening sheet casting, and an auxiliary alloy casting sheet is obtained; the step of quickly hardening the cast sheet comprises refining and casting in sequence. Titanium and vanadium are introduced into the auxiliary alloy casting piece, a specific rapid hardening casting piece technology is matched, the obtained auxiliary alloy casting piece is rich in spherical