Reduction of injection molded silica glass defects and enhancement of glass quality via water debinding

Abstract

Fabrication of silica glass with complex shapes and high precision could be achieved via thermal debinding followed by sintering of the injection molded silica–plastic nanocomposite (i.e. green parts). However, the thermal debinding of the green parts usually leads to the formation of internal cracks in the specimens, reducing the quality of the sintered glass. Here, we suppressed the crack formation and improved the quality of silica glass fabricated by the classical injection molding (IM) and sintering method via the water debinding process. The role of water debinding in the quality enhancement of the resultant silica glass was investigated by electron microscopy, IR spectroscopy, and zeta potential measurements. Our results suggest that the use of water debinding prior to thermal debinding for the green parts results in the improvement of the packing of silica nanoparticles. This is due to the increase in both the surface charge and densification of the silica nanoparticles, which results in the reduction of micro-sized pores in the network and thus improves the transparency and homogeneity of the sintered glass. These findings could be used to optimize the IM approach for the production of high quality pure silica glass with high productivity for application in various fields, e.g., photonics and pharmaceutical fields.