Enhanced microwave dielectric properties of NdNbO4 ceramic by Ta5+ substitution

NdNbO4 ceramics based on Ta5+ substitution with enhanced microwave dielectric properties were prepared via conventional mixed oxide routes. Packing fractions and bond valences were calculated. The effects of Ta5+ substitution on the microstructures and microwave dielectric properties of NdNbO4 ceramics were investigated. Microscopic analysis showed that the specimens presented single NdNbO4 phase in the range of x = 0.0 to 0.06, while with a further increase of the amount of Ta5+ substitution, NdTa7O19 phase appeared in the system. The substitution of Ta5+ for Nb5+ effectively enhanced the quality factor of NdNbO4 ceramics. An optimal microwave dielectric properties with Q × ƒ = 51,000 GHz was obtained for Nd1.02(Nb1−xTax)0.988O4 (x = 0.06) ceramics sintered at 1275 °C for 4 h.