This study demonstrates an advancement in the synthesis of high-performance forsterite (Mg2SiO4) ceramics through phase engineering and process optimization. We developed a novel approach that combines quartzing heat treatment with controlled particle size reduction to achieve exceptional dielectric properties. By subjecting amorphous SiO2 to a pre-sintering quartzing treatment (970 ◦C for 8 h), we successfully stabilized the quartz phase. Systematic variation of silica particle size (5–70 μm) via high-energy milling allowed precise control over reaction kinetics and phase evolution. The optimized ceramic exhibited outstanding microwave dielectric properties, including a high quality factor (Q = 234,000 at 10 GHz) and a low dielectric constant (εᵣ < 6). Compared to previous works, the obtained value is within the highest range of quality factors ever reported. Microstructural characterization revealed the complete elimination of porosity in samples with sub-5 μm silica particles (F845-15H), achieving 96 % of the theoretical density through optimized sintering at 1450 ◦C. The quartzing pretreatment was particularly effective in suppressing characteristic dielectric loss peaks between 10.5 and 11.9 GHz by controlling the quartz-to-cristobalite phase ratio. Rietveld refinement and FESEM analysis confirmed the critical role of phase stabilization in enhancing dielectric performance.
