晶间复合添加Ti/Al, Ti/Cu对烧结Nd-Fe-B磁体磁性能与显微组织的影响

EFFECTS OF Ti/AI, Ti/Cu ADDITION ON MAGNETIC PROPERTIES AND MICROSTRUCTURE OF SINTERED Nd - Fe - B MAGNETS

研究了在烧结Ｎｄ－Ｆｅ－Ｂ磁体晶间复合添加高熔点元素Ｔｉ和低熔点元素Ａｌ或 Ｃｕ对显微组织和磁性能的影响。实验结果表明，适量的Ｔｉ和Ａｌ或Ｃｕ复合添加能够显著提 高Ｎｄ－Ｆｅ－Ｂ磁体的矫顽力，过量的Ｔｉ则会导致矫顽力和退磁曲线矩形度的下降。显微组 织分析表明，矫顽力的提高可归结于晶间相的均匀分布和主相晶粒边界的规则化。在添加过 量Ｔｉ的磁体中发现少量晶粒的反常长大现象，从而导致矫顽力的损失和退磁曲线矩形度的 恶化。与单独添加的效果相比较发现，晶间复合添加高熔点与低熔点合金元素是一条提高烧 结Ｎｄ－Ｆｅ－Ｂ磁体矫顽力的有效途径。

The effects of high - melting elements Ti together with low - melting elements Al or Cu on mi- crostructure and magnetic properties of Nd -Fe - B magnets were investigated . It was found that an appropri- ate amount of Ti could significantly enhance the coercivity of magnets. However, higher amounts of Ti addi- tion led to a loss of coercivity and a demagnetization curve with poor rectangularity. Microstructural studies re- vealed that the improvement of the coercivity could be attributed to a well - distributed intergranular phase and even grain boundary of main phase. An abnormal growth of main phase was found in the magnets with higher amounts of Ti addition, resulting in a loss of coercivity and a demagnetization curve with poor rectangulatity. By comparing the effect of the combined addition with that of the single addition(Al, Cu or Ti) , it was found that the combined addition of high - melting and low - melting elements may be a better approach to modify the coercivity of Nd - Fe - B magnets.