(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 研究一級(jí)時(shí)效、兩級(jí)時(shí)效和多級(jí)時(shí)效處理對(duì)Sm(CoFe0.20Cu0.12Zr0.03)7.5磁性能的影響，并引入擴(kuò)散長(zhǎng)度探討材料時(shí)效處理動(dòng)力學(xué)機(jī)制。結(jié)果表明，一級(jí)時(shí)效處理的溫度越高，材料的擴(kuò)散系數(shù)DT1越大，達(dá)到某一特定擴(kuò)散長(zhǎng)度所需的時(shí)間越少，即磁體達(dá)到矯頑力峰值所需的時(shí)間越短。在連續(xù)降溫處理過(guò)程中，達(dá)到某一特定擴(kuò)散長(zhǎng)度所需的時(shí)間與降溫幅度和擴(kuò)散系數(shù)有關(guān)，Cu原子的擴(kuò)散長(zhǎng)度是連續(xù)降溫時(shí)效處理過(guò)程的主要影響因素。Sm2Co17型永磁材料的典型顯微結(jié)構(gòu)是由2׃17R主相和1׃5胞壁相所組成的胞狀結(jié)構(gòu)以及片狀結(jié)構(gòu)構(gòu)成。當(dāng)一級(jí)時(shí)效溫度T1和二級(jí)時(shí)效溫度T2固定時(shí)，達(dá)到特定擴(kuò)散長(zhǎng)度所須的時(shí)間與這2個(gè)溫度下磁體的擴(kuò)散系數(shù)成反比。Cu原子沿片狀相的擴(kuò)散速率比沿晶內(nèi)體擴(kuò)散速率大，當(dāng)磁體內(nèi)片狀相含量較多時(shí)，Cu原子的擴(kuò)散系數(shù)可大大增加，可有效縮短擴(kuò)散所需時(shí)間。
關(guān)鍵字: 稀土永磁；時(shí)效處理；胞狀結(jié)構(gòu)；擴(kuò)散長(zhǎng)度
（State Key Laboratory of Powder Metallurgy, Central South University,Changsha 410083, China）
Abstract:The magnetic properties and one-step aging, two-step aging and multilevel aging treatment of Sm(CoFe0.20Cu0.12Zr0.03)7.5 were investigated, and the kinetic mechanism was analysed by inducing diffusion length. The results show that the higher the first step aging temperature, the larger the diffusion coefficient DT1 and the shorter the time necessary to achieve a certain diffusion length, which implies the shorter the time to reach the coercivity peak value. During the continuous cooling treatments, the time necessary to achieve a certain diffusion length is related to the temperature decreasing rate and diffusion coefficient, and the diffusion length of Cu is the main factor, respectively. The microstructure of Sm2Co17-based rare-earth permanent magnets consists of 2׃17R main phase, 1׃5 cell boundary phase and lameller phase. When the aging temperature T1 and T2 are fixed, the time necessary to achieve a certain diffusion length is inverse-proportional to the diffusion coefficient. Because the diffusion rate of Cu in the lameller phases is larger than that in the grains, the diffusion coefficient of Cu can be increased with increasing the content of lameller phase, and the diffusion time can be shortened effectively.
Key words: rare-earth permanent magnets; aging treatment; cellular structure; diffusion length
