The commonly used base material is ethyl silicate, also known as ethyl orthosilicate, with a structural formula of Si(OC 2 H 5 ) 4 , and dimer and trimer condensates are also synthesized in addition to monomers. Ethyl silicate reacts with water to eventually form silica . In this kind of paint, the paint containing more zinc powder is called zinc-rich paint, and the heat-resistant temperature can reach 370°C. The paint containing aluminum powder is called heat-resistant aluminum powder paint, and the heat-resistant paint can reach 410°C. Adding mica, asbestos and other powders or titanium dioxide , chromium oxide, etc. can improve the strength of the coating film and prevent the coating from cracking and falling off.
After hydrolysis and polymerization, ethyl silicate finally becomes a silica network cross-linked polymer , so the coating prepared by it is generally included in the inorganic type coating. Because the polymer structure is similar to silica, it has good heat resistance, water resistance, and chemical resistance, and it is increasingly widely used. Ethyl silicate coatings dry quickly and can be cured at room temperature, especially suitable for construction in environments with high humidity . Alcohols are generally used as solvents. The zinc-rich primer prepared by it has good corrosion resistance . It has high heat resistance, generally can withstand 400 ℃ for a long time , and can withstand higher .
Organic titanate heat-resistant coating
The base material of this coating is 4-n-butyl titanate, namely Ti(OC 4 H 9 ) 4 , which forms , but the film-forming performance is very poor, and aluminum can be added to Form a continuous coating film. After heat treatment at 300~500 ℃ , a high-strength coating film with a heat resistance of 500 ℃ can be obtained. The price of this coating is higher than that of silicone resin heat-resistant coating. Zinc-rich butyl titanate is used as a primer, and aluminum powder-based titanate is used . The temperature resistance can reach 400 ℃ .
Heat-resistant coatings not only require high temperature resistance, but also require anti-corrosion properties, anti-rust, anti-sticking, anti-thermal oxidation, and wear resistance due to different purposes . For example, various heat exchangers and petroleum cracking furnaces require heat resistance, rust resistance, and corrosion resistance; motor products require heat resistance and insulation; the surface of aviation and aerospace vehicles requires heat resistance, wear resistance, corrosion resistance, and oxidation resistance; artillery, etc. The launch tube of thermal weapons requires resistance to heat oxidation and weather resistance; boilers and cooking utensils require protection from high temperature oxidation.
At present, a lot of progress has been made in inorganic high-temperature coatings in the fields of aviation and aerospace. Civilian heat-resistant coatings are still mainly based on silicone coatings.
The main direction of future research is to develop high-temperature-resistant resins that can withstand higher temperatures and have good film-forming and construction properties as base materials for heat-resistant materials, and new pigments and fillers that can significantly improve the various properties of base materials under high-temperature conditions. Variety.
