论文部分内容阅读
本文对多晶NiAl以及不同粒径的NiAl样品的磁性进行了研究．结果表明：大块多晶NiAl合金的磁化率X很小．大约为3×10－5／g，其比磁化强度σ几乎不随温度变化，在1．5－150K温度范围，平均粒径为8．6nm的制备态纳米NiAl的σ随温度的增高而显著下降，由σ-T曲线可得到其居里温度Tc为124K．制备态的纳米NiAl经退火处理后得到的平均粒径分别为12，18和21nm的三种样品的σ比普通多晶NiAl高两个量级，而且在1．5—300K温度范围，σ随温度变化很小．表明多晶NiAl合金在其晶粒纳米化后发生了非磁性－磁性转变。
In this paper, the magnetic properties of polycrystalline NiAl and NiAl samples with different particle sizes were studied. The results show that the magnetic susceptibility X of bulk polycrystalline NiAl alloy is very small. About 3 × 10-5 / g, the specific magnetization σ almost does not change with temperature, in the temperature range of 1.5-150K, the average particle size of 8.6 nm NiAl nano-prepared state with the temperature increased significantly decreased , Curie temperature Tc is obtained from σ-T curve 124K. The three samples with average particle sizes of 12, 18 and 21 nm, respectively, obtained by annealing after preparation of nanosized NiAl have two orders of magnitude higher σ than ordinary polycrystalline NiAl. In the temperature range of 1.5-300 K, σ Little change in temperature. It shows that the polycrystalline NiAl alloy undergoes non-magnetic-magnetic transition after its grain size is nanometer.