Mo元素掺杂对氧化铝基陶瓷/金属复合材料微观形貌及介电性能的影响

Influence of Mo Doping on the Microstructure and Dielectric Property of Alumina Ceramic/metal composites

摘要:

采用粉末冶金法制备了Mo掺杂的Al2O3基陶瓷/金属复合材料（Al2O3/Mo），利用X射线衍射、扫描电镜等测试分析方法研究了Mo掺杂对复合材料微观形貌及介电性能的影响。结果表明：Al2O3/Mo复合材料主要由Al2O3相和Mo相组成，未出现新相。Mo主要分散在Al2O3晶界，并且随着Mo掺杂量的增加，Al2O3晶粒尺寸逐渐减小、材料气孔率逐渐增加。当Mo掺杂量小于20wt.%时，复合材料电阻率（>1012Ω?cm）与相对介电常数（8-9）没有明显变化；而当Mo掺杂量大于20wt.%，Mo由弥散相转变为连续相，复合材料的体电阻率急剧下降到1010Ω?cm；当Mo掺杂量达到40wt.%时，由于复合材料中Mo已经形成连续的贯穿网络，体电阻率下降趋势减缓，稳定在10Ω?cm左右。因此，通过调控Al2O3基体中的Mo掺杂量及相分布，可以制备出具有不同电阻率的陶瓷/金属复合材料。

Abstract:

Mo-doped Alumina (Al2O3/Mo) ceramic composites were prepared by powder metallurgical process. The influence of Mo doping amount on the microstructure and electrical properties of the composites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and other testing analysis methods. The results show that the composites were composed of Al2O3 and Mo phases and without any impurities. When the amount of Mo is below 20wt.%, there are no obvious changes in resistivity (>1012Ω?cm) and permisitvity(8-9) for the composites, but the refaining of grain. When doping amount over 20wt.%, the Mo transforme from dispersed phase into the continuous phase while volume resistivity decrease to 1010Ω ? cm shaply; When doping amount is 40wt.%, since the throughout matrix of Mo is formed, the volume resistivity decrease slow, steady at about 10Ω ? cm. Therefore, by adjusting the amount and phase distribution of Mo in Al2O3 matix, ceramic/metal composite materials with different resistivity can be prepeared.