Abstract: Disclosed is a sintered body composition used in improved diffusion efficiency of heavy rare earth elements RH, and related sintered permanent magnet and preparation methods. The sintered body includes Nd2Fe14B crystal phase as a primary phase, and a rare earth rich phase as a grain boundary phase. The sintered body includes a composition expressed by RaBbGacCudAleMfCogFebalance; wherein R is one or more selected from rare earth elements, and R includes Nd; M is one or more selected from the group consisting of Zr, Ti, and Nb; and wherein “a” satisfies 13%?a?15.3%; “b” satisfies 5.4%?b?5.8%; “c” satisfies 0.05%?c?0.25%; “d” satisfies 0.08%?d?0.3%; “e” satisfies 0?e?1.2%; “f” satisfies 0.08%?f?0.2%; and “g” satisfies 0.8%?g?2.5%. Grains in Nd2Fe14B crystal phase have average size L of 4-8 ?m, and the relationship between L and t for grain boundary phases average thickness is: ?=t/L, wherein ? is defined as 0.009???0.012.

Abstract: Disclosed is a sintered body, a sintered permanent magnet and preparation methods. The sintered body comprises Nd2Fe14B crystal phase as a primary phase and a rare earth rich phase as a grain boundary phase and has a composition expressed by composition formula RaBbGacCudAleMfCogFebalance; R is one or more selected from rare earth elements, and R must comprise Nd; M is one or more selected from the group consisting of Zr, Ti, and Nb; a satisfies 13%?a?15.3%; b satisfies 5.4%?b?5.8%; c satisfies 0.05%?c?0.25%; d satisfies 0.08%?d?0.3%; e satisfies 0?e?1.2%; f satisfies 0.08%?f?0.2%; g satisfies 0.8%?g?2.5%; grains in Nd2Fe14B crystal phase have average size L of 4-8 ?m, grain boundary phases have average thickness t with unit of ?m; the relation of t and L is: ?=t/L; and ? is defined as 0.009???0.012. The present disclosure improves diffusion efficiency of heavy rare earth elements RH.