High dielectric constant in Al-doped ZnO ceramics using high-pressure treated powders

Abstract Pure and Al-doped ZnO ceramics were prepared by conventional sintering high pressure treated nano powders at 1150 °C for 2 h, and the effect of Al-doping on the microstructure and dielectric properties were mainly investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results revealed that Al reacted with ZnO and formed ZnAl 2 O 4 nano-precipitates on the grain boundaries. Small amount of ZnAl 2 O 4 nano-precipitates (i.e.  4 at 1 kHz) of ZnO ceramics. And the dielectric behavior can be well-explained by Maxwell–Wagner relaxation.