Reaction sintering and mechanism of microwave dielectric ceramic with K 2 NiF 4 structure and perovskite structure

We use reaction sintering method (RS) to prepared 0.85(1 − x CaTiO 3− x LnAlO 3 )–0.15Ca 1.15 Ln 0.85 Al 0.85 Ti 0.15 O 4 (Ln = Nd, Y) ceramics. CLnC ceramics have two phase structures of perovskite and K 2 NiF 4 . The ceramic grains are obvious solid solutions, and gradually enlarge with increasing the sintering temperature. CNdC ceramics exhibit good microwave dielectric properties in the sintering temperature range of 1475–1575 °C. As the sintering temperature increases from 1475 to 1500 °C, the density of CNdC ceramics tends to be stable, fluctuates around 4.6 g/cm 3 . The ε r reaches maximum value at 1500 °C then gradually decreases. As the sintering temperature increases from 1500 to 1550 °C, the Q × f keeps a stable value from 41,953 to 44,188 GHz. As the sintering temperature was 1500 °C, the CNdC ceramics achieved the best microwave dielectric properties with ε r = 37.15, Q × f = 44,188 GHz, τ f = − 4 ppm/°C. The sintering temperature of CYC ceramics was relatively low and the ceramics sintered at 1450 °C achieved good microwave dielectric properties of ε r = 38.3, Q × f = 29,620 GHz, τ f = 0.03 ppm/excellent. It is worth noting that CYC ceramics have an excellent τ f , which can ensure excellent temperature stability during application.