纳米Ni-20Fe颗粒增韧Al_2O_3复合材料的力学性能与磁性能

Mechanical and magnetic properties of nano-Ni-20Fe toughening alumina-based nanocomposites

用机械化学及热压烧结方法成功制备了高致密Ni-20Fe/Al2O3纳米复合材料。通过X-ray、FE-SEM、力学性能、磁性能测试,结果表明,复合后材料断裂韧性从纯-αAl2O3相的4.7 MPa.m1/2提高到6.2 MPa.m1/2(19%(Ni-20Fe)/Al2O3),断裂方式有沿晶断裂和穿晶断裂两种。当Ni-20Fe合金的体积百分数达到19%时,复合材料的饱和磁化强度达33 emu/g,矫顽力为200 Oe,且在低于500℃的情况下,矫顽力基本不随温度而变,具有良好的磁热稳定性。

Ni-20Fe/Al2O3 nanocomposites with high relative density （D≥98%） were fabricated using the mechanochemical method and the hot-pressing process. The fracture toughness is increased from 4. 7 to 6. 2 MPa-m^1/2 as Ni-20Fe volume fraction increases from 0 to 19%. Both the intergranular and the transgranular fractures are observed on the fracture surface by FE-SEM. When 19% Ni-20Fe is added, the composite Ms is 33 emu/g, Hc is 200 Oe, and Hc keeps constant below 500℃, which shows good magnetic heat stability.