采用多元醇还原法,以乙二醇为反应溶剂和还原剂,PVP为稳定剂,制备尺寸约30nm、在极性溶剂中分散良好的NiPd纳米粒子。采用XRD、ICP和TEM等手段对所制备的不同组成的纳米粒子进行表征,证明所制纳米粒子为NiPd合金,采用PVP为稳定剂有效地阻止了纳米粒子的团聚与氧化。所制备的纳米粒子的磁学性质及磁热效应结果表明,NiPd纳米合金具有较大的矫顽力,表现为铁磁性,且随着组分中Ni含量的增加,纳米合金的饱和磁化强度和磁热效应均增加,纳米粒子在60kHz、7.5kA/m的交变磁场作用下,试样的悬浮液升温可达14℃左右,显示出较高的磁热性能。
Aqueously well-dispersed NiPd nanoparticles with a dimension of about 30 nm were prepared by a modified polyol reduction process, using glycol as both solvent and reductant, and PVP as stabilizing agent. The as-synthesized nanoparticles with different composition were characterized by XRD, ICP and TEM. It is proved that the nanoparticles are NiPd alloy, and the PVP prevents them from agglomeration and oxidation. The magnetic properties and heat effect under external alternating magnetic field reveal that the obtained NiPd nanoalloy is ferromagnetic material and has bigger coercive force; additionally, the saturation magnetization and heat generation ability of the nanoalloy are improved by the increasing of Ni content. When the nanoparticles were exposed to an external alternation magnetic field of 60 kHz and 7.5 kA/m, the samples show high heat generation ability, with the suspension temperature increasing by 14 ℃.