A Viable Route for Dense TiO2 with a Low Microwave Dielectric Loss

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 δ, was 46 000 GHz, ∼7.6 times higher than 6000 GHz (Q