Casting and characterization of LiMgPO_4 glass free LTCC tape for microwave applications

摘要

The LiMgPO_4 ceramic has been prepared through the solid state ceramic route. The powder has an average particle size of 1.1 μm and BET surface area of 2.7 m~2 g~(-1). Good dispersion of LiMgPO_4 has been achieved in ethanol/xylene mixture with the addition of 2 wt.% fish oil. The tape casting slurry of LiMgPCU with typical pseudoplastic behavior has been prepared and cast into thin tapes of thickness 70 μm. LiMgPQ_4 green tape shows a tensile strength of 0.22 MPa and average surface roughness of 0.25 fun. The green tape has an ε_r of 3.2 and tan 5 of 0.0688 at 5 GHz. The thermo-laminated tape (4 layers) sintered at 950°C/2h shows good microwave dielectric properties: ε_r = 6.4 and tan δ = 0.0002. LiMgPO_4 has a coefficient of thermal expansion of 10.5 ppm/°C and thermal conductivity of 7.1 W m~(-1) K~(-1).