((中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083))
摘 要: 采用透射電子顯微鏡(TEM)、掃描電子顯微鏡(SEM)、磁力顯微鏡(MFM)和原位X射線衍射(XRD)等探討Sm2Co17型稀土永磁材料的胞狀結(jié)構(gòu)、疇結(jié)構(gòu)和相結(jié)構(gòu)及其對(duì)磁性能的影響，制備使用溫度為500 ℃的高溫稀土永磁材料。結(jié)果表明，Sm(CoFe0.11Cu0.10Zr0.03)7.5具有很好的高溫穩(wěn)定性，500 ℃時(shí)的磁性能為：Br=0.708 T，Hci=646.7 kA/m，BHmax=85.4 kJ/m3；其磁疇寬度遠(yuǎn)小于晶粒尺寸，但大于胞狀結(jié)構(gòu)的尺寸，使用溫度較高的磁體具有較小的磁疇和胞狀結(jié)構(gòu)；當(dāng)使用溫度小于300 ℃時(shí)，Sm2Co17型磁體內(nèi)存在的相結(jié)構(gòu)為2׃17R、2׃17H和1׃5相，矯頑力主要受1׃5相的釘扎而產(chǎn)生；當(dāng)300 ℃＜t＜tc1:5時(shí)，部分1׃5相轉(zhuǎn)變成中間相并最終轉(zhuǎn)變成2׃7相，磁體的矯頑力將由1׃5相釘扎和2׃7相形核所控制；當(dāng)t≥tc1:5時(shí)，磁體的矯頑力將全部由非磁性1׃5相和2׃7相形核所控制。
關(guān)鍵字: Sm2Co17型高溫稀土永磁；胞狀結(jié)構(gòu)；疇結(jié)構(gòu)；矯頑力
（(State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)）
Abstract:High temperature Sm2Co17-based permanent magnets used at 500 ℃ were attained and the cellular structure, domain structure and crystalline phase were investigated by transmission electron microscopy (TEM), scaning electron microscopy (SEM), magnetic force microscopy (MFM) and in-sute X-ray diffractometry. Sm(CoFe0.11Cu0.10Zr0.03)7.5 shows better high temperature properties at 500 ℃ with Br=0.708 T, Hci=646.7 kA/m, BHmax=85.4 kJ/m3. It is discovered that the domain spacing is much smaller than the grain size and larger than the cellular structure. The magnet used at higher temperature shows smaller domain spacing and cell size. When the temperature is lower than 300 ℃, the microstructure of the magnet consists of 2׃17R phase, 1׃5 phase and lamella phase, and the the 1׃5 phase acts as a barrier for domain wall displacements. In the intermediate temperature range (300℃＜t＜tc1:5), a part of 1׃5 phase transform to 2׃7 phase，and the coercivity mechanism changes to pinning at the 1׃5 phase and nucleation at the 2׃7 phase. With increasing the temperature higher than the Curie temperature of the 1׃5 cell walls a nucleation mechanism at the 1׃5 non-magnetic phase and 2׃7 phase may be dominant.
Key words: Sm2Co17 type high temperature permanent magnet; cellular structure; domain structure; coercivity
