Effect of V₂O₅ doping on the sintering and dielectric properties of M-phase Li_1+x-yNb_1-x-3yTi_x+4yO₃ ceramics

The effect of the addition of V₂O₅ on the structure, sintering and dielectric properties of M-phase (Li_1+x-yNb_1-x-3y-Ti_x+4_y O₃ ceramics has been investigated. Homogeneous substitution of V⁵⁺ for Nb⁵⁺ was obtained in LiNb_0. 6(_1+x-y)-V_0.6xTi_0.5O₃ for x ≤ 0.02. The addition of V₂O₅ led to a large reduction in the sintering temperature and samples with x = 0.02 could be fully densified at 900°C. The substitution of vanadia had a relatively minor adverse effect on the microwave dielectric properties of the M-phase system and the x = 0.02 ceramics had ε_r = 66, Q×f = 3800 at 5.6 GHz, and τ_f = 11 ppm/°C. Preliminary investigations suggest that silver metallization does not diffuse into the V₂O₅-doped M-phase ceramics at 900°C, making these materials potential candidates for low-temperature cofired ceramic (LTCC) applications.