Fabrication of transparent silica glass and evaluation of silica particle dispersibility in silica slurries based on the solubility parameters of the slurry components

Silica particles were dispersed in 11 acrylic monomers at various concentrations. The dispersibility of the silica particles was evaluated based on the viscosity of the slurry. Furthermore, the relationship between the viscosity of the slurry and the solubility parameters (SPs) of the silica particles and acrylic monomers was investigated. When the SPs of the silica particles and acrylic monomers were close, the viscosity of the silica slurry decreased and high concentrations of the silica particles could be dispersed in the acrylic monomers. Therefore, SP can be used for predicting the dispersibility of silica particles. The prepared slurry was then used to fabricate sintered silica glass. Silica slurry was cured through photopolymerization to obtain a green body, which was then heattreated at 850 degrees C in air atmosphere and sintered at 1710 degrees C under vacuum to obtain sintered silica glass. Transparent sintered silica glass with no cracks was obtained using 4-hydroxybutyl acrylate, which has a similar SP to that of silica particles, as a solvent. The obtained sintered silica glass exhibited a transmittance of 92 % at a wavelength of 400 nm. In the ultraviolet region, light absorption originated from two-coordinated Si in the glass. The absorption spectrum in the infrared region showed an extremely low peak of the SiOH group, indicating that low-OH silica glass was obtained. Thus, this study provides a new method for fabricating silica glass and provides a method of selecting solvents for the slurries used in powder sintering.