What is silica sol precision casting? Why can silica sol be used for precision casting?

Silica sol (colloidal silica), also known as silicic acid solution, is a colloidal dispersion of amorphous silica aggregate particles in water. Silica sol has a wide water loss temperature range, which will not only destroy its bonding strength, but also make its three-dimensional structure more stable, resulting in higher bonding strength. It is a good inorganic binder for precision casting.

In the 1960s, silica sol began to be used as a binder for precision casting. Since the 1990s, due to increased pressure for environmental protection, silica sol has gradually replaced the widely used ethyl silicate hydrolyzate, which is seriously polluting and expensive. Currently, polymer-reinforced fast-drying silica sol is widely used as a binder in the world's investment casting industry.

Precision casting is a general term for the process of obtaining castings with precise dimensions. Investment casting is also called lost wax casting. Its products are precise and complex, close to the final shape of the part, and can be used directly without or with a small amount of processing. This is an advanced near net shape process. The process includes: selecting appropriate investment materials (such as paraffin) to make investment molds; repeatedly dipping refractory paint (main component is silica sol) and spraying refractory sand on the investment mold, hardening the shell and drying; melting the inner investment mold, Obtain the mold cavity; bake the shell to obtain sufficient strength and burn off the remaining investment material; pour the required metal materials; solidify and cool, shell and clean the sand to obtain high-precision finished products.

Silica sol is used in precision casting. Due to its good bonding ability and filling performance, the shell produced has high strength, high gloss and easy demoulding, and is widely used in this field.