Definition of anticorrosive coating: Anticorrosive coating refers to a class of liquid or solid materials that can form a film under certain conditions to protect, decorate, or other special functions (insulation, rust, mildew, heat resistance, etc.). Because the early paints mostly used vegetable oil as the main raw material, they were also called paints. Synthetic resins have mostly or completely replaced vegetable oils, so they are called coatings. The role has three main points: protection, decoration, and concealment of product defects, and enhance the value of the product.
 
In anticorrosive coating formulations, silica acts as a thickening thixotropic and anti-settling additive. Thickening, playing the role of anti-settling, suspension, etc., so that fillers and other additives can be evenly dispersed in the resin without precipitation; thixotropic effect makes the coating have superior anti-sagging performance and thick coating performance, Improve construction performance.

Mechanism: When silica is dispersed in a non-polar liquid, silanol groups on the surface of different particles form bridges through hydrogen bonding interactions. This three-dimensional structure constitutes a thickening effect. When the system is subjected to mechanical external forces, such as stirring or shaking, this structure is damaged. The type and duration of the mechanical external forces acting determine the degree of damage. As a result, the thickened system becomes liquid again. If you keep it still, the silica particles will be connected again to restore the original viscosity. This phenomenon is called pseudoplasticity.

Anticorrosive coatings are mostly epoxy resin, polyurethane resin, vinyl resin and other systems. These resins have strong polar groups. Generally, hydrophilic fumed silica is used, which is prone to solvent-based effects. The consistency and suspension effect are very good, but when placed for a week to ten days, the polar groups destroy the hydrogen bonds forming the network structure, leading to the cracking of the hydrogen bonds, thinning, no thixotropy, and filler precipitation. Anticorrosive coatings are recommended to use hydrophobically modified fumed silica, which is highly stable and avoids solvent-based effects.
     
The thickening and thixotropic effects of silica depend to a large extent on the dispersion strength, and at least a high-speed disperser is required for dispersion. The best dispersion effect can be achieved by rotor rotor dispersion or ball mill, three-roller dispersion.
   
The best choice of dispersion method and equipment depends on the consistency of the system. Sometimes we recommend to first disperse the entire silica with some liquid or some formula ingredients, and then add the remaining liquid and other formula ingredients to adjust the silica content to the required ratio of the formula. In principle, the thickening effect of silica increases with the decrease of the basic particle size. However, as the particle size increases, higher shear forces are required to achieve its thickening effect. .