Nik Akmar Rejab

The influence of La₂O₃ addition (x = 1,3,5 and 7 wt.%) on phases formation, microstructural and electrical properties of ZTA ceramic prepared via conventional solid-state method was studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Hall Effect measurement, respectively. The XRD peaks show the presence of three different phases (Al₂O₃, Zr_0.82Y_0.18O_1.91 and La_0.85Al_11.6O_18.678). In addition, the bulk density of the present samples decreased remarkably while the porosity increases. The SEM results show that the grain morphology varies significantly with increasing La₂O₃ content. Increasing amount of La₂O₃ has increased the grain size which is beneficial to improve the electrical properties of ZTA system. The electrical resistivity of the ZTA-La₂O₃ composites ceramic decreased with increasing initial La₂O₃ content. The lowest electrical resistivity 13.2 (Ω.cm) was obtained for ZTA-7wt.% La₂O₃ composites ceramic. Therefore, the results confirm that better physical and electrical properties can be obtained by controlling amount of La₂O₃ addition into ZTA.