Glass-Free KxBa1−xGa2−xGe2+xO8 Ceramics for Low-Temperature Cofired Ceramics Technology: Synthesis, Phase Transitions, Sintering, and Microwave Dielectric Properties |
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Authors: | Ni Qin Marjeta Maek Krmanc Danilo Suvorov |
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Affiliation: | Advanced Materials Department, Jo?ef Stefan Institute, Ljubljana 1000, Slovenia |
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Abstract: | K x Ba1? x Ga2? x Ge2+ x O8 (0.6≤ x ≤1) polycrystalline ceramics are potential materials for glass-free low-temperature cofired ceramics (LTCC) substrates. We have made a comprehensive study of the kinetics of the monoclinic-to-monoclinic P 21/ a ? C 2/ m phase transition. The low-temperature-stable P 21/ a phase with a high Q × f value was synthesized using a subsolidus method and was well sintered at the LTCC temperature with a H3BO3 additive. A good combination of low sintering temperature (910°–920°C), high Q × f values (96 700–104 500 GHz), low permittivities (5.6–6.0), and a small temperature coefficient of resonant frequency (~?20 ppm/°C) was obtained for ceramics with x =0.67 and 0.9 and with 0.1 wt% of H3BO3. |
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