摘要
通过机械合金化结合等放电离子烧结技术,采用不同烧结温度制备名义成分相同的Mn_(1.2)Fe_(0.8)P_(0.73)Ge_(0.27)样品。使用X射线衍射仪(XRD)、差示扫描热量分析仪(DSC)、扫描电镜(SEM)研究了不同烧结温度对材料的成分、晶粒大小和磁热性能的影响。结果表明,材料均保持六方Fe_2P结构。随烧结温度的升高,居里温度下降,晶粒长大,熵变上升;而杂相Ge_6Fe_3Mn_4向Mn_(1.2)Fe_(0.8)P_(0.73)Ge_(0.27)主相转化,而氧化物的含量基本不发生变化。
Mn_(1.2)Fe_(0.8)P_(0.73)Ge_(0.27) alloys with the same initial component were prepared at different sinter temperatures by mechanical alloying and spark plasma sintering technique. The magnetocaloric properties and microstructures were investigated by X-ray diffraction( XRD),differential scanning calorimetry( DSC),scanning electron microscope( SEM). The results show that samples crystalize in the hexagonal Fe_2P-type structure. When the sintering temperatures rises,the Tc decreases,grain grows and the entropy change increases. The Ge_6Fe_3Mn_4 transformed to Mn_(1.2)Fe_(0.8)P_(0.73)Ge_(0.27) with the rise of sintering temperature,while no change with MnO content were found.
引文
[1] GLANZ J. Making a bigger chill with magnets[J].Science,1998,279(5359):2045-2045.
[2] TEGUS O,FUQUAN B,DAGULA W,et al. Magneticentropy change in Mn1. 1Fe0. 9P0. 7As0. 3-xGex[J]. Journal of Alloys and Compounds,2005,396(1/2):6-9.
[3]闫洪波,杨泽中,汪建新,等.基于专利分析的磁制冷技术应用研究[J].科技管理研究,2018,38(15):199-204.
[4] PECHARSKY V K, GSCHNEIDNER K A. Phase relationships and crystallography in the pseudobinary system Gd5Si4-Gd5Ge4[J]. Journal of Alloys and Compounds,1997,260(1/2):98-106.
[5] HU F X,SHEN B G,SUN J R,et al. Influence of negative lattice expansion and metamagnetic transition on magnetic entropy change in the compound La Fe11. 4Si1. 6[J]. Applied Physics Letters,2001,78(23):3675-3677.
[6]陈伟,钟伟.室温磁致冷最新进展[J].功能材料,1998(3):236-239.
[7] TEGUS O,BRUCK E,BUSCHOW K H J,et al.Transition-metal-based magnetic refrigerants for roomtemperature applications[J]. Nature,2002,415(6868):150.
[8] LIU D M,HUANG Q Z,YUE M,et al. Temperature,magnetic field,and pressure dependence of the crystal and magnetic structures of the magnetocaloric compound Mn1. 1Fe0. 9(P0. 8Ge0. 2)[J]. Physical Review B,2009,80(17):174415.
[9] YUE M,LI Z Q,WANG X L,et al. Crystal structure and magnetic transition of MnFePGe compound prepared by spark plasma sintering[J]. Journal of Applied Physics,2009,105(7):07A915.
[10] LIU D M,YUE M,ZHANG J X,et al. Origin and tuning of the magnetocaloric effect in the magnetic refrigerant Mn1. 1Fe0. 9(P0. 8Ge0. 2)[J]. Physical Review B,2009,79(1):014435.
[11] DAGULA W,TEGUS O,Li X W,et al. Magnetic properties and magnetic-entropy change of MnFeP0. 5As0. 5-xSix(x=0-0. 3)compounds[J]. Journal of Applied Physics,2006,99(8):08Q105.
[12]张虎,刘丹敏,王少博,等. Mn2-xFexP1-yGey(x=0. 8、0. 9,y=0. 2、0. 24、0. 26)磁制冷材料的制备工艺及磁热性能研究[J].功能材料,2013,44(21):3103-3107.
[13]孟庆普,刘丹敏,张隐奇,等. Mn1. 2Fe0. 8P0. 74Ge0. 26化合物的微观形貌及性能研究[J].电子显微学报,2015,34(4):313-316.
[14]刘俊亮,张作贵,宓小川,等. X80钢中残余奥氏体定量分析的XRD与EBSD法比较[J].电子显微学报,2010,29(1):689-692.