Synthesis and characteristic of titanium dioxide (TiO2) doped nickel oxide (NiO) dielectric materials

NiO-based ceramic showed the dielectric constant with the range of 103 – 105, but it has high dielectric loss. In this research, TiO2 act as dopant on NiO and the effect of TiO2 addition into NiO was investigated. Ni1-xTixO1+x was prepared via solid-state reaction method with different TiO2 compositions, which are 0.01, 0.02, 0.03, 0.05 and 0.10 mole %. The results of these compositions were compared to the pure NiO composition. The preparation started with the powder mixing process for 24 hours and followed by calcination process at 950 °C for 4 hours. Then, the calcined powders were compacted into 6 mm pellet shape with 250 MPa pressure. Those pellets were sintered at 1250 °C for 5 hours. XRD results showed that sample 1 to 3, which are pure NiO, 0.01 and 0.02 mole % of TiO2 compositions produced single NiO crystalline phase, while sample 4 to 6, which are 0.03, 0.05 and 0.10 mol % of TiO2 showed there are secondary TiO2 phases. Others, SEM analysis showed that increasing TiO2 concentration make the grain size increase, but 0.02 mole % of TiO2 gave the largest grain size among all samples, that showed 0.02 mole % is the optimum TiO2 concentration for grain size enlargement. Furthermore, the increasing of TiO2 concentration causes decrement trend for bulk density of Ni1-xTixO1+x pellet. In dielectric test, the addition of 0.03 mole % of TiO2 shows the result of the highest dielectric constant with value of 4.5114 and 0.05 mole % of TiO2 gives the result of lowest dielectric loss with value of 0.53.