Silica sol (colloidal silicon dioxide), also known as a silicic acid solution, is a colloidal dispersion of amorphous silica aggregate particles in water. Silica sol has a wide dehydration temperature range, which not only destroys its bonding strength but also makes 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 the increasing pressure of environmental protection, silica sol has gradually replaced the widely used ethyl silicate hydrolyzate, which is heavily polluted and expensive. At present, polymer-reinforced quick-drying silica sol is widely used as a binder in the investment casting industry around the world.
Precision casting refers to the general term for the process of obtaining castings with precise dimensions. Investment casting is also called lost wax casting. Its products are sophisticated, close to the final shape of the part, and can be used directly without machining or with a small amount of machining. This is an advanced near-net shape process. The process includes: selecting a suitable investment material (such as paraffin) to make an investment pattern; repeating the steps of dipping refractory coating (the main component is silica sol) and spraying refractory sand on the investment pattern, hardening the shell and drying; melting the inner investment pattern, Obtain the mold cavity; bake the shell to obtain sufficient strength and burn off the residual investment material; pour the required metal material; solidify and cool, shell, and remove sand to obtain a high-precision finished product.
Silica sol is used in precision casting. Due to its good bonding ability and filling performance, the shell made of it has high strength, high gloss, and easy demoulding, so it is widely used in this field. According to the specific user requirements, it is divided into surface silica sol and back silica sol, which consumes a lot.
The Silica Sol casting process in HXN foundry is operated with the most advanced technology in China. We can produce top-level investment castings in a variety of dimensions and shapes. In this process, all metal alloys are available, we can customize investment castings according to your material specifications, and even material compositions are feasible for production. To ensure the best quality, we will do quality control in each investment casting process.