High performance anisotropic NdFeB flexible bonded magnets prepared by magnetic alignment with temperature utilizing HDDR NdFeB powder

High performance anisotropic NdFeB flexible bonded magnets were prepared by a two-step method which includes calendering and magnetic alignment steps utilizing hydrogenation-disproportionation-desorption-recombination (HDDR) NdFeB powder, and their magnetic and mechanical properties were investigated. It is found that the degree of alignment (DOA) of the flexible bonded magnets goes up sharply. The maximum energy product (BH)_max is 97 kJ·m^-3 for the composition of 96.5% magnetic powder, 1% coupling agent, and 2. 5% bonded rubber after heated at 120℃ for 30 min during magnetic alignment, while the coercivity of the flexible bonded magnets only decreases by 1.3%, which further proves the feasibility of the two-step method in industrial production. Because the mechanical properties of the flexible bonded magnets will deteriorate with the amount of epoxy resin lubricant increasing, the mass fraction of epoxy resin lubricant should be less than 1%.