Preparation and characterization of ultra-low-temperature of (BiAg)0.5MoO4 dielectric ceramic doped with Y2O3

Abstract

This paper reports on the use of solid-phase sintering to prepare (BiAg)0.5MoO4 (BAMO) ceramic doped with Yttrium oxide (Y2O3), which is less expensive than the dopants currently used in the commercial formulation of powders for the fabrication of multilayer ceramic capacitors. Experiments were conducted to determine the means by which Y2O3 doping concentration and sintering temperature affect the phase evolution, microstructure, and dielectric properties of BAMO ceramic. Our results reveal the following important findings. Sintering Y2O3-doped BAMO ceramic at 600 °C resulted in the formation of secondary phases (Bi2Mo2O9 and γ"-Bi2MoO6) and constrained grain growth. Sintering at 600 °C promoted the precipitation of silver ions (Ag+) from the starting material (Ag2O) to agglomerate at grain boundaries, leading to a decrease in insulation resistance and breakdown voltage. Interestingly, 5 wt% Y2O3-doped BAMO ceramic sintered at 600 °C presented good dielectric characteristics: εr = 26.6, Q × f value = 22194 GHz, and temperature coefficient of resonant frequency = +14 ppm/°C. Our findings demonstrate that single-phase BAMO ceramic with good density characteristics can be produced via sintering at 600 °C for 1 h. The ultra-low-temperature production of this dielectric material would allow for co-firing with aluminum electrode to further reduce manufacturing costs.