Synthesis and characterization of titanium dioxide doped nickel oxide dielectric materials

Abstract

Nickel oxide (NiO) belongs to the transition metal oxide family, having good dielectric constant
with the range of 10³ – 10⁵, but it has high dielectric loss. In this research, the effect of titanium
dioxide (T_iO₂) addition into N_iO was investigated. Generally, T_iO₂ was used in the application of
electrical ceramic, catalysts, electric conductors and chemical intermediates. Ni_1-xT_ixO_1+x was
prepared via solid-state reaction method with 6 different TiO2 compositions. 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 under pressure of 250
MPa pressure. Three pellets were made for each TiO₂ composition. Those pellets were sintered at
1250 °C for 5 hours. XRD results showed that pure N_iO at 0.01 and 0.02 mole % of T_iO₂
compositions produced single N_iO crystalline phase, while 0.03, 0.05 and 0.10 mol % of T_iO₂
showed the T_iO₂, instead of N_iO phases. SEM analysis showed that increasing T_iO₂ concentration
make the grain size increase, with 0.02 mole % of TiO2 gave the largest grain size, shows that 0.02
mole % is the optimum T_iO₂ concentration for grain size enlargement. Furthermore, the bulk
density of Ni_1xTi_xO1+xpellet was reduces at higher T_iO₂ concentration. In dielectric test, the addition
of 0.03 mole % of T_iO₂ gave the highest dielectric constant with value of 4.51 x 1014 and 0.05 mole
% of T_iO₂ gives the result of lowest dielectric loss (0.53).