Enhanced sintering ability and microwave dielectric properties of LiZnNbO4 ceramics with pretreatment of raw materials

• An effective method (abbreviated as LZN2) was shown to improve the microwave performance of LiZnNbO4 ceramic with low cost.
• In this paper, we got access to starting powders with smaller particle sizes by physical grinding method.
• The ceramics prepared by LZN2 method exhibited more uniform microstructure and excellent microwave dielectric performance.
• Moreover, LZN2 method lowered its sintering temperature to further application in LTCC.

In present study, an approach to further improve the sintering ability and microwave dielectric properties of LiZnNbO4 (LZN) ceramics was reported. For the conventional ceramic technique (abbreviated as LZN1), the raw materials of Li2CO3, ZnO and Nb2O5 were directly used without further processing, while those for LZN2 were ball milled before mixing. The powders from LZN2 tends to be smaller and uniform and the ceramic has higher densities than that of LZN1 at low sintering temperatures (<980 °C), which significantly improves the microwave dielectric properties of LZN ceramic. In addition, in a wide sintering temperatures range (980 °C–1100 °C), LZN2 keeps a stable permittivity of εr ∼ 15 and quality factor of Q × f ∼ 60000 GHz (at ∼9 GHz). Especially, LZN2 ceramic sintered at 1070 °C exhibits very good microwave dielectric performance with εr = 15.6, Q × f = 85,310 GHz (at ∼9.1 GHz), τf = −63.7 ppm/°C, indicating that the pretreatment of raw materials is a simple and an effective strategy to obtain a dense LZN ceramic with more excellent dielectric properties and stability.