磁制冷是一种利用材料的磁热效应进行制冷的新型制冷技术,相比于传统气体压缩制冷,因其绿色环保、高效节能等优点而备受关注。在众多磁相变合金材料中,人们对Mn_2Sb基亚铁磁相变合金研究甚少。文章研究了Cr取代Mn后亚铁磁性Mn_(2-x)Cr_x...磁制冷是一种利用材料的磁热效应进行制冷的新型制冷技术,相比于传统气体压缩制冷,因其绿色环保、高效节能等优点而备受关注。在众多磁相变合金材料中,人们对Mn_2Sb基亚铁磁相变合金研究甚少。文章研究了Cr取代Mn后亚铁磁性Mn_(2-x)Cr_xSb_(0.95)In_(0.05)(x=0.05,0.09,0.13)合金的磁性和磁热性能。室温XRD数据表明合金在室温附近以四角Cu_2Sb型结构为主相。由于反铁磁中有高磁响应,因此从XRD图谱中能观察到少量的铁磁MnSb杂相。随着温度的降低,在这些合金中,发生了亚铁磁到反铁磁的一级磁致弹性转变。同时,在亚铁磁区域观察到两个自旋重新取向转变。由于反铁磁-亚铁磁的转变过程中磁化强度突变,使得在Mn_(1.91)Cr_(0.09)Sb_(0.95)In_(0.05)合金中在0~10 k Oe的磁场变化中获得高达1.63 J/kg·K的大磁熵变。目前的研究可能有助于研究和开发新的磁性冷材料。展开更多
Proper utilization of the FeSO4·7H2O waste slag generated from TiO2 industry is an urgent need, and Fe3O4 particles are currently being widely used in the wastewater flocculation field. In this work, magnetite wa...Proper utilization of the FeSO4·7H2O waste slag generated from TiO2 industry is an urgent need, and Fe3O4 particles are currently being widely used in the wastewater flocculation field. In this work, magnetite was recovered from ferrous sulphate by a novel co-precipitation method with calcium hydroxide as the precipitant. Under optimum conditions, the obtained spherical magnetite particles are well crystallized with a Fe304 purity of 88.78%, but apt to aggregate with a median particle size of 1.83 μm. Magnetic measurement reveals the obtained Fe304 particles are soft magnetic with a saturation magnetization of 81.73 A-m2/kg. In addition, a highly crystallized gypsum co-product is obtained in blocky or irregular shape. Predictably, this study would provide additional opportunities for future application of low-cost Fe3O4 particles in water treatment field.展开更多
文摘磁制冷是一种利用材料的磁热效应进行制冷的新型制冷技术,相比于传统气体压缩制冷,因其绿色环保、高效节能等优点而备受关注。在众多磁相变合金材料中,人们对Mn_2Sb基亚铁磁相变合金研究甚少。文章研究了Cr取代Mn后亚铁磁性Mn_(2-x)Cr_xSb_(0.95)In_(0.05)(x=0.05,0.09,0.13)合金的磁性和磁热性能。室温XRD数据表明合金在室温附近以四角Cu_2Sb型结构为主相。由于反铁磁中有高磁响应,因此从XRD图谱中能观察到少量的铁磁MnSb杂相。随着温度的降低,在这些合金中,发生了亚铁磁到反铁磁的一级磁致弹性转变。同时,在亚铁磁区域观察到两个自旋重新取向转变。由于反铁磁-亚铁磁的转变过程中磁化强度突变,使得在Mn_(1.91)Cr_(0.09)Sb_(0.95)In_(0.05)合金中在0~10 k Oe的磁场变化中获得高达1.63 J/kg·K的大磁熵变。目前的研究可能有助于研究和开发新的磁性冷材料。
基金Project(2013A090100013)supported by the Special Project on the Integration of Industry,Education and Research of Guangdong Province,ChinaProject(201407300993)supported by the High-Tech Research and Development Program of Xinjiang Uygur Autonomous Region,China
文摘Proper utilization of the FeSO4·7H2O waste slag generated from TiO2 industry is an urgent need, and Fe3O4 particles are currently being widely used in the wastewater flocculation field. In this work, magnetite was recovered from ferrous sulphate by a novel co-precipitation method with calcium hydroxide as the precipitant. Under optimum conditions, the obtained spherical magnetite particles are well crystallized with a Fe304 purity of 88.78%, but apt to aggregate with a median particle size of 1.83 μm. Magnetic measurement reveals the obtained Fe304 particles are soft magnetic with a saturation magnetization of 81.73 A-m2/kg. In addition, a highly crystallized gypsum co-product is obtained in blocky or irregular shape. Predictably, this study would provide additional opportunities for future application of low-cost Fe3O4 particles in water treatment field.
