Method of Improving Dielectric Properties of AlN Ceramic

Abstract

AlN-Mo composite ceramics were prepared by spark plasma sintering (SPS) with AlN and Mo, introduction of Mo particles into the AlN matrix was through direct current magnetron sputtering, sol-gel and blending technology methods. The effect of Mo particles on densification, electrical conduction and dielectric properties of AlN ceramic was studied by XRD, SEM, dielectric frequency spectrum. The results indicate that dielectric constant of AlN-0.26vol.%Mo composite ceramics obtained by sputtering increase by 22.5% at 1MHz as compared to the pure AlN sample; AlN-18vol.%Mo composite ceramics prepared with Mo powder coated with Al2O3 show insulator character and good dielectric properties; dielectric constant and loss of the composite ceramics increase with increasing the content of the elongated shape Mo particles, the highest dielectric constant and loss will be obtained when AlN-12vol.%Mo content is 30wt.% ( =98.41, tgδ=0.018 at 1MHz), the value of electrical resistivity decreases rapidly from 1.32×104 to 3.16×101Ω•cm when AlN-12vol.%Mo weight fraction increases from 30% to 40%.