Casting and characterization of LiMgPO4 glass free LTCC tape for microwave applications

Abstract

The LiMgPO4 ceramic has been prepared through the solid state ceramic route. The powder has an average particle size of 1.1 mu m and BET surface area of 2.7 m (2) g(-1). Good dispersion of LiMgPO4 has been achieved in ethanol/xylene mixture with the addition of 2 wt. % fish oil. The tape casting slurry of LiMgPO4 with typical pseudoplastic behavior has been prepared and cast into thin tapes of thickness 70 mu m. LiMgPO4 green tape shows a tensile strength of 0.22 MPa and average surface roughness of 0.25 mu m. The green tape has an epsilon(r) of 3.2 and tan delta of 0.0688 at 5 GHz. The thermo-laminated tape (4 layers) sintered at 950 degrees C/2 h shows good microwave dielectric properties: epsilon(r) = 6.4 and tan delta = 0.0002. LiMgPO4 has a coefficient of thermal expansion of 10.5 ppm/degrees C and thermal conductivity of 7.1 W m (-1) K-1