Silica sol binder

Silica sol is a kind of high quality adhesive commonly used in investment casting.It is silicon dioxide melt, by amorphous silicon dioxide small particles dispersed in the water and form a stable colloidal solution, also known as colloidal silicon dioxide.The appearance is light milky white or with opalescence.

Silica sol is easy to use, easy to mix into high quality powder liquid ratio, coating stability is good.No chemical hardening is needed in shell manufacturing, the process is simple, the shell produced has good high temperature performance, high temperature strength and high temperature deformation resistance.However, the wettability of silica sol coating to wax film is poor, surfactant should be added to improve the coating adhesion.In addition, the drying speed of silica sol shell is slow, the wet strength of silica sol shell is low, and the period of shell making is long.

Because the silica sol shell does not grow hairs during storage, it is very suitable for the coating with surface inoculant, it can make the surface inoculant play a good role, get the surface grain refined castings.The composite shell with silica sol as surface layer and ethyl silicate as back layer has been widely used in production.Silica sol is a water-based binder, and there is no air pollution when making the shell. In today's increasingly strict environmental protection requirements, the application of this kind of binder has a rising trend.