Effects of adding TEOS on sintering process, morphology and microwave dielectric properties of Y3Al5O12 ceramics

The influence of the TEOS (Si(OC 2 H 5 ) 4 ) addition, which decomposes into SiO 2 at high temperature, on the sintering process, morphology, and microwave dielectric properties in Y 3 Al 5 O 12 (YAG) ceramics were investigated in this work. The Y 3 Al 5 O 12  +  x wt.% TEOS (0≤ x  ≤ 1) ceramics were synthesized through solid-state reaction. The XRD results indicated that all YAG samples possessed a pure cubic garnet structure. The dense, pore-free crystalline microstructure of the specimen was measured by SEM. The Rietveld method was employed to refine the lattice parameters of YAG samples. Results showed that the samples' cellular parameters decreased with increasing amounts of TEOS. The addition of TEOS lowered the sintering temperature and improved the Q  ×  f values of Y 3 Al 5 O 12 ceramics. The YAG system was added by 0.5 wt% TEOS can be exhibited excellent microwave dielectric properties with ε r =10.82, Q  ×  f  = 229,423 GHz, τ f  = -29.1 ppm/°C sintering at 1670 °C for 12 h.