Preparation and microwave dielectric properties of multilayer Li_(1.075)Nb_(0.625)Ti_(0.45)O_3 co-fired ceramics with aqueous tape casting

摘要

Multilayer Li_(1.075)Nb_(0.625)Ti_(0.45)O_3 (LNT) ceramics for low temperature co-fired ceramic (LTCC) application were prepared by aqueous tape casting. The rheological test indicated that the aqueous slurries exhibited a typical shear-thinning behavior without thixotropy suitable for tape casting process. The green tapes with 2 wt% V_2O_5 addition have satisfactory mechanical properties. Scanning electron microscopy studies revealed that the green tapes have a smooth defect-free surface and that the sintered LNT ceramics have a fine grain microstructure with a uniform grain size. Therefore, aqueous tape casting is suitable for the manufacture of high performance multilayer LNT ceramics. Silver inner-electrode was sintered with LNT tapes at 900 °C, and no reaction been observed between LNT ceramic and sliver layers. The addition of V_2O_5 does not induce much degradation on the microwave dielectric properties. In the case of 2 wt% V_2O_5 addition, the ceramics show good microwave dielectric properties of ε_r = 65, Q × f = 6,350 GHz. It represents that LNT ceramics could be promising for multilayer LTCC application.