Author(s): MBARI, ETAHERI NASSAJ, HTAGHIPOUR ARMAKI
Microwave dielectric ceramics with the composition of Li2ZnTi3O8 – 4 wt% TiO2 were synthesized by the conventional solid-state reaction. 4 wt% TiO2 powders with different particles size were added to the Li2ZnTi3O8 ceramic. Then the ceramic samples were sintered at temperatures 1075°C, 1050°C, 1000°C, and 950°C for 4 h. The effect of the particles size of TiO2 additive on the microwave dielectric properties of the ceramics has been investigated. In the study two categories of particles size of TiO2 additive have been used; (i) Nanoparticle (50 nm), (ii) Micron sized (40, 5, 1 μm) powder. X-ray showed that the TiO2 additive has not solved in the LZT structure and has not almost undergone chemical reaction with the LZT ceramic. The results showed that the addition of TiO2 nanoparticles to the LZT ceramics significantly improved the density and a dense and uniform microstructure and also abnormal grain growth were observed by SEM. The use of TiO2 nanoparticle reduces porosity and leads to an increase in green density. The maximum density was found to be 98.5% of the theoretical density and the best relative permittivity of 28, quality factor of 68000 GHz and τf value of −2 ppm/°C were obtained for the samples added with 4 wt% of the TiO2 nanoparticles, sintered at 1050°C for 4 h.