Microwave sintering of BaTiO₃ ceramics

Barium titanate and BaTiO₃-based multilayer capacitors were sintered in a commercial microwave oven. The oven was equipped with a 2.45 GHz continuous-wave magnetron with a maximum power output of 650 watts. Microwave-absorbing setters made of SiC were used to offset thermal losses from the samples and allow sintering temperatures (\u3e1325°C) to be achieved. Pure samples were pressed from commercial BaTiO₃ powder and microwave sintered to about 90% of theoretical density. Multilayer capacitors were obtained from commercial manufacturers and used in all sintering experiments. A comparison between microwave sintered material and identical samples sintered in a conventional electric furnace revealed no difference in measured dielectric properties. The temperature uniformity within the microwave oven and the relative energy efficiency of the sintering process were also examined. An experimental design using a single-mode resonant cavity for heating was proposed --Abstract, page ii