A novel LiNb_(0.6)Ti_(0.5)O_3 microwave dielectric ceramic with Ca substitutions

摘要

Highlights•A novel LiNb0.6Ti(0.5−x)Ca1.231xO3ceramic with near zero τƒwas synthesized.•The Ca substitutions could lower the τƒof LiNb0.6Ti0.5O3ceramics effectively.•Ca5Nb4Ti3O21phase has a high εrand a negative τƒby the mixture calculation.AbstractA novel microwave dielectric ceramic LiNb0.6Ti0.5O3(LNT) with Ca substitutions LiNb0.6Ti(0.5−x)Ca1.231xO3was synthesized by solid-state method. It was found that with Ca substitutions, the temperature coefficient of resonant frequency τƒcould be adjusted to zero, due to the appearance of the second phase Ca5Nb4Ti3O21. The τƒof the Ca5Nb4Ti3O21phase is −144.3ppm/°C through the simulation and numerical value calculation. Furthermore, the LiNb0.6Ti(0.5−x)Ca1.231xO3ceramic shows a higher dielectric constant εrand a denser microstructure. The LiNb0.6Ti(0.5−x)Ca1.231xO3ceramic with x=0.03 sintered at 1100°C for 2h shows excellent microwave dielectric properties: εr=76.89, Q׃=4064GHz, τƒ=0.25ppm/°C.