Customizable flame‐spheroidized submicron glass particles with controlled CaO–Al ₂ O ₃ –SiO ₂ compositions

Abstract Glass particles are extensively utilized in electronic device substrates, conductive pastes for batteries, and various sealing and bonding applications due to their tunable material properties, such as refractive index, thermal conductivity, and high‐frequency characteristics. With the miniaturization of electronic components driven by advancements in data communication and device performance, there is a growing demand for glass particles with controlled size, shape, and composition to densely fill fine spaces. Traditional methods producing particles of 10.0–20.0 µm are inadequate as size reduction becomes critical. Although crushing glass to about 1.0 µm is a common approach, it is time‐consuming, energy‐intensive, and lacks control over particle size and shape. In this study, we aimed to synthesize spherical CaO–Al 2 O 3 –SiO 2 glass particles within the submicron range (0.1–1.0 µm) with precisely controlled chemical compositions using a flame process. We evaluated the effects of precursor concentration, reactor temperature, and residence time on the glass particle properties and the formation mechanisms for each condition. The results confirmed successful submicron‐size control and spheroidization and precise compositions, demonstrating the significant potential of flame method in producing tailored glass particles for advanced electronic applications.