The application of silane coupling agents in the pretreatment of metal corrosion protection is a completely new application of silane. This technology was also studied abroad in the 1990s, but has not yet been industrialised on a large scale. As the silane coupling agent can be formed after hydrolysis of the trihydrocarbon silanol, the hydroxyl groups of the silanol can react with each other to form a layer of cross-linked dense net-like hydrophobic film. As the surface of this film has organic functional groups that can react with the resin, the adhesion to the paint film will be greatly improved, as will the resistance to corrosion, friction and impact. At the same time rubber additives, due to the silane film itself has hydrophobic, has a certain anti-corrosion effect, and with the density of the film is proportional.
The superiority of the phosphate film is illustrated by comparing the effect with the phosphate film. For example, by comparing different metal substrates treated with silane systems with iron phosphate, zinc phosphate and chromate, it was found that the outstanding features of the silane coupling agent treatment were:

1. corrosion protection can be achieved without the need for painting;
2. simple process compared to phosphating process, no heavy metal containing waste water, good environment;
3. Micro/molecular bridges improve the adhesion of the paint film on the substrate.

Additives In many areas, silane treatment exhibits the same or better anti-corrosion effect than the existing technology. These characteristics offer a wide range of promising applications and development prospects, especially in the automotive and motorbike industries as well as in vehicle and mechanical engineering.
Silane coupling agents, as structurally unique silicone compounds, bridge the gap between inorganic and organic materials and improve the defects of many materials. The development of silane reagents for corrosion protection technology on metal surfaces is taking shape and has obvious advantages.
Currently, phosphating and passivation processes are widely used for the typical coating of metallic materials. Although the processes are mature, the discharge of waste and disposal costs are high. With the gradual increase in environmental requirements and environmental awareness, in particular the reduction in permitted emissions of chromium in various countries, other processes and chemical treatment reagents are being considered to replace the old phosphating and passivating processes. The use of silane reagents in metal corrosion protection and surface pre-treatment of metallic materials can indeed produce encouraging results and is now becoming a new field of application for silane reagents. With zero pollution, good corrosion resistance of treated parts and strong bonding to the coating, it would have a profound impact on the metal materials processing industry if it could replace the heavily polluting phosphating and passivating pre-treatment processes in industry.