Influence of the Al content on properties of nanometer ZAO powder

ZAO precursors were synthesized by uniform precipitation-method from zinc nitrate (Zn (NO₃)₂), aluminum nitrate (Al (NO₃)₃) and carbamide. The nanometer ZAO powders with different Al content were obtained after heat treat ZAO precursors at 400°C for 3h. The crystalline phase, microstructure and the dielectric property for different samples were analyzed and the influence of Al content on the crystalline phase, microstructure and the dielectric property were investigated. The XRD results indicate that the spectra of the ZAO powder is almost the same to that of pure ZnO powder when the Al content is below 11at%, indicating that the Al atoms do enter the ZnO crystal lattice and substitute the position of Zn. The structure of nanometer ZAO particles with the hexagonal system and wurtzite structure is global or similar one. The dielectric real part and dielectric loss of the ZAO powders is dominated by the Al content in the ZAO powder. With the increase of Al concentration, both the dielectric real part and dielectric loss increase sharply and reaches the maximum value when the Al content is 11at%. When the Al content is above 11at%, both dielectric real part and dielectric loss decrease obviously with the increase of Al content due to the formation of ZnAl₂O₄ in the samples.