(Ni,Co)/Al_2O_3复合材料的浸渍-还原制备及其电性能

The impregnation-reduction preparation and electrical properties of(Ni,Co)/Al_2O_3 composite

采用无压烧结法于1250℃制得气孔率分别为51%、58%、62%的Al2O3陶瓷基体。通过浸渍-还原法在陶瓷孔壁上负载金属Ni和Co,控制样品的总金属含量为5wt%左右。研究不同气孔率对金属陶瓷电性能的影响。利用XRD对复合材料进行物相分析;利用阻抗分析仪对材料的高频(10 MHz^1GHz)电性能进行测试分析。结果表明,还原后的复合材料中只含有氧化铝、金属钴和金属镍;随着金属陶瓷气孔率的增加,材料介电常数实部明显减小,这是由于空气含量增加,以及金属间距增大引起的。因此,通过改变气孔率可以对金属/陶瓷实现电参数调控。

The matrixes of porous Al2 O3 ceramic with the porosity of 51%,58% and 62% are prepared by pressureless sintering at 1250℃.And the metal/ceramic composite consisting of nickel and cobalt particles hosted in porous Al2 O3 is prepared using a facile Impregnation-Reduction process.For the composites,the microstructure of the composite is analyzed by XRD,and the final phase composition after reduction is only aluminum oxide,metal cobalt and nickel.Then the impedance,dielectric properties and conductive mechanism of(Ni,Co)/Al2 O3 composites are investigated experimentally in the frequency range from 100MHz to 1GHz by using the Impedance Analyzer.The results showed that with the increasing of porosity,the real part of permittivity of metal/ceramic composites decrease.Further analysis indicates that the increase of air content and the distance between metal particles becomes further apart,reduce the effective the permittivity.That is to say,the tunable electrical parameters of metal/ceramic can be realized.