Method for preparing N48H sintered neodymium-iron-boron magnet high in heat stability

The invention discloses a method for preparing a N48H sintered neodymium-iron-boron magnet high in heat stability. According to the method, chemical components and the magnetic microstructure of neodymium-iron-boron crystal particles are changed by adding dysprosium, cobalt, copper, aluminum, niobium, gallium and other elements. Main alloy and auxiliary alloy are prepared through the near-rapid solidification strip casting (SC) technology, the hydrogen decrepitation (HD) technology and the jet milling (JM) technology, the main alloy and the auxiliary alloy are mixed according to a certain proportion, and finally the N48H sintered neodymium-iron-boron permanent magnet high in heat stability is obtained. The prepared sintered neodymium-iron-boron magnet has the advantages of being low in temperature coefficient and resistant to high temperature. Besides, the magnet does not contain expensive rare earth terbium, and the formula cost advantage is remarkable.