Tb-Al-Cu/Nd复合扩散源对烧结钕铁硼磁性能的影响OA

Grain boundary diffusion technology has emerged as a pivotal approach to overcome bottlenecks of high cost and significant remanence loss in traditional single-alloy methods by precisely regulating the distribution of heavy rare earths(HREs),thereby markedly enhancing the coercivity of NdFeB magnets.This study proposed composite diffusion sources formed by blending Tb-Al-Cu HRE alloys with pure Nd powder at varying ratios,systematically investigating their diffusion modification effects on both HRE-free and HRE-containing substrates.Experimental results demonstrated that under optimal diffusion source ratios,the maximum coercivity enhancements for the two substrates reached 1.036 T and 0.959 T,respectively,with remanence attenuation controlled within 0.59 kGs and 0.43 kGs.When TbAlCu-to-pure-Nd ratio was 3∶2(for HRE-free substrates)or 2∶3(for HRE-containing substrates),the magnets exhibited optimal comprehensive performance,achieving 48UH and 45EH grade levels,respectively.Microstructural analysis revealed that HRE-free substrates developed increased grain boundary phases,refined grains,and core-shell structures after diffusion,while HRE-containing substrates showed a significant increase in non-magnetic grain boundary phases.By designing composite diffusion sources,this study achieved remarkable magnetic performance improvements with low HRE consumption,offering a novel strategy for the green preparation and resource-efficient utilization of high-performance NdFeB magnets.