Synthesis, characterization, and microwave dielectric properties of Ni0.5Ti0.5NbO4 ceramics through the aqueous sol–gel process

• The nanosized powders were obtained at 800 °C by the aqueous sol–gel process.
• The Ni0.5Ti0.5NbO4 ceramics were sintered at 1100 °C for 2 h.
• The best microwave properties were εr = 59.95, Q × f = 15094 GHz, τf = 111.15 ppm/°C.

A kind of dielectric ceramic based on tetragonal rutile structure Ni0.5Ti0.5NbO4 (NTN) was prepared by the aqueous sol–gel process. The main objective was to significantly reduce the ceramic sintering temperature by sol–gel process while maintaining acceptable properties. A further objective was to optimize the three key properties-relative permittivity (εr), quality factor (Q·f) and the temperature coefficient of resonant frequency (τf). Highly reactive nanosized NTN powders with particle sizes of 20–50 nm were successfully obtained at 800 °C as precursors. Sintering characteristics and microwave dielectric properties of Ni0.5Ti0.5NbO4 ceramics were studied depending on sintering temperatures ranging from 850 °C to 1200 °C. The excellent microwave properties of Ni0.5Ti0.5NbO4 (NTN) ceramic was found at 1100 °C with εr = 59.95, Q·f = 15,094 GHz, τf = 111.15 ppm/°C. The lower sintering temperatures and excellent microwave dielectric properties would make these ceramics promising for application in microwave components.

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