A Viable Route for Dense TiO2 with a Low Microwave Dielectric Loss
Abstract:Dense, high-purity TiO2 was prepared from commercially available powders. These powders were deagglomerated, colloidally stabilized in aqueous NH3, followed by screening to remove residual agglomerates. Homogeneous compacts were formed using colloidal-filtration followed by sintering. TiO2 with >99.5% density and 400 MPa flexural strength was obtained at a sintering temperature as low as 1000°C. The dielectric loss of this TiO2 was 1.4 × 10−4 at 6.4 GHz at room temperature. This implied that the product of the quality factor and frequency, (Q×f )=f/tan , was 46 000 GHz, ∼7.6 times higher than 6000 GHz (Q<2000 at 3 GHz) reported previously. This high-quality factor is attributed to the low sintering temperature as well as a homogeneous dense microstructure with 2.2 m grain size. The process described can be applied to realize complex TiO2 structures in new microwave antenna concepts, that require components with a high dielectric constant and low dielectric loss.
Document Type: Research Article
Affiliations: 1: ElectroScience Laboratory, Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43212 2: Group Inorganic Materials Science, Department of Materials Science & Engineering, The Ohio State University, Columbus, Ohio 43210-1178 3: Department of Electrical Engineering, University of South Florida 4202 E. Fowler Ave. ENB 118 Tampa, Florida 33620
Publication date: April 1, 2010