(中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 采用透射電鏡(TEM)、場發(fā)射掃描電鏡(FESEM)、X射線衍射(XRD)等方法系統(tǒng)研究Sm(CobalFe0.108Cu0.131Zr0.042)7.0在830 ℃時效處理10~30 h過程中的微結(jié)構(gòu)演變及磁性能。結(jié)果表明:合金時效處理后形成由菱方Sm2Co17R主相和六方Sm(Co,Cu)5胞壁相構(gòu)成的胞狀結(jié)構(gòu)、疊加在胞狀結(jié)構(gòu)之上的六方富Zr片狀結(jié)構(gòu)和少量富Zr的Sm(CoCuFeZr)x析出相。隨830 ℃時效處理時間由10 h延長到30 h，Sm2Co17R主相的尺寸由80~110 nm長大到150 nm，富Zr片狀相的密度增大，富Zr的Sm(CoCuFeZr)x析出相的體積分數(shù)增多。富Cu的SmCo5胞壁相和富Zr的Sm(CoCuFeZr)x析出相通過釘扎疇壁為合金提供高的室溫和高溫矯頑力。磁性能測試結(jié)果表明:剩磁Br隨830 ℃時效時間的延長而單調(diào)增大，內(nèi)稟矯頑力Hci在830 ℃處理20 h時達最大值2417.9 kA/m，在測試溫度為500 ℃時仍具有高的Hci，為693.5 kA/m。
關(guān)鍵字: Sm2Co17型稀土永磁材料；時效處理；析出物；胞狀結(jié)構(gòu)
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Microstructure and magnetic properties of Sm(CobalFe0.108Cu0.131Zr0.042)7.0 annealed at 830 ℃ for 10-30 h have been systematically investigated by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and magnetic measurement. It is found that the heat-treated alloy consists of the rhombohedral Sm2Co17 phase as the cell and the hexagonal Sm(CoCu)5 as the cell boundary phases. In addition, the structure contains Zr-rich plate-like phase on the basal planes, running across both the cells and cell boundaries, as well as Zr-rich Sm(CoCuFeZr)x precipitates. It is obvious that the annealing time significantly affects the microstructure. With increasing the annealing time from 10 h up to 30 h, the Sm2Co17R cell size increases from 80-110 nm to 150 nm and becomes uniform, the density of platelet phase and the content of Sm(CoCuFeZr)x precipitates also increase. The Cu-rich SmCo5 sell boundary phase and Zr-rich Sm(CoCuFeZr)x precipitates are responsible for the high coercivity at both room and high temperature. Magnetic analysis shows that the remanence Br enhances from 0.625T to 0.845T with the annealing time increasing from 10 to 30 h. The intrinsic coercivity Hci reaches the maximum value of about 2417.9 kA/m at room temperature and 693.5 kA/m at 500 ℃ after annealing for 20 h.
Key words: Sm2Co17-based high temperature permanent magnet; annealing treatment; precipitate; cellular structure
