Polysilazane has a wide and important application in ceramic coatings. The following is a detailed introduction for you:
Advantages of using polysilazane for ceramic coatings
Good film-forming properties: Polysilazane itself has excellent film-forming characteristics and can form continuous and dense thin films on different substrate surfaces conveniently and uniformly through various conventional coating processes such as spraying, immersion, spin coating, etc. This lays the foundation for constructing high-quality ceramic coatings. For example, on the surface of metal components with complex shapes, the use of spray coating technology to apply polysilazane solution can effectively cover various parts and form a complete coating structure.
Good high-temperature stability: Polysilazane coatings can exhibit excellent stability in high-temperature environments. After high-temperature treatment, polysilazane undergoes reactions such as cracking and cross-linking, transforming into ceramic phase and forming ceramic coatings with high temperature resistance. This coating can be used for a long time in high-temperature working conditions such as high-temperature components of aerospace engines and the inner walls of industrial furnaces, effectively resisting the erosion of high-temperature gases, flames, etc., and ensuring the normal operation of components.
Strong chemical resistance: It has good resistance to various chemical substances, whether it is acidic or alkaline solutions, organic solvents, or chemical media in some corrosive industrial environments. The ceramic coating formed by polysilazane can provide good protection, preventing these chemicals from contacting the surface of the substrate, preventing the substrate from being corroded or damaged, and extending the service life of the substrate. For example, coating the surface of equipment involved in acid-base treatment in chemical production with ceramic coatings derived from polysilazane can greatly enhance the corrosion resistance of the equipment.
Strong adhesion to substrates: Polysilazane exhibits strong adhesion to many common substrates, such as metals (such as steel, aluminum, copper, etc.), ceramics, glass, etc. In the process of forming ceramic coatings, it can tightly bond with the substrate surface through various methods such as chemical bonding and physical adsorption, and is not prone to coating peeling or flaking, ensuring that the coating can stably function during long-term use. For example, coating a polysilazane ceramic coating on the surface of a metal cutting tool can firmly adhere to the tool even during stress processes such as cutting.
The principle of converting polysilazane into ceramic coatings
Curing reaction stage: Polysilazane first undergoes its own curing reaction, under certain conditions (such as heating, adding curing agents, etc.), cross-linking occurs between molecular chains, gradually transforming from liquid to solid, and initially forming a relatively stable coating structure on the substrate surface. During this process, the active groups in polysilazane participate in the reaction, making the molecular structure denser and preparing for subsequent conversion into ceramic coatings.
High temperature cracking stage: After solidification, the polysilazane coating is subjected to high-temperature cracking at higher temperatures (usually several hundred degrees Celsius or even thousands of degrees Celsius, depending on the type and application requirements of the polysilazane). During this process, chemical bonds such as silicon nitrogen and carbon silicon bonds in polysilazane molecules break and rearrange, releasing some small molecules (such as hydrogen, ammonia, etc.). At the same time, elements such as silicon, carbon, and nitrogen recombine to gradually form ceramic phases, such as silicon nitride (Si3N4), silicon carbide (SiC), and other ceramic materials, ultimately completing the transition from polysilazane coating to ceramic coating.
Application Fields of Polysilazane Ceramic Coatings
Aerospace field: Coating high-temperature components such as turbine blades and combustion chamber walls of aircraft engines with ceramic coatings derived from polysilazane can improve the high-temperature resistance, oxidation resistance, and thermal shock resistance of the components. When the engine is working, these components have to withstand extremely high temperatures and complex thermal stress changes. Ceramic coatings can effectively protect the components, reduce damage caused by high-temperature gas erosion, extend the service life of the components, and ensure the reliability and safety of the engine.
In the field of automobile manufacturing, for components such as pistons and cylinders in automobile engines, polysilazane ceramic coatings can reduce the friction coefficient between components, improve wear resistance, and also provide some insulation, which helps to improve the efficiency and performance of the engine. In addition, in the exhaust system of automobiles, coatings can withstand the erosion of high-temperature exhaust gases, prevent component rust and corrosion, and enhance the durability of the exhaust system.
In the field of industrial manufacturing: By utilizing the high temperature and corrosion resistance properties of polysilazane ceramic coatings on the inner walls of industrial furnaces, high-temperature pipelines, reaction vessels, and other equipment surfaces, the frequency of equipment maintenance and replacement can be reduced, production costs can be lowered, and production efficiency can be improved. For example, in high-temperature kilns used in ceramic production, coatings can prevent the kiln wall material from being eroded at high temperatures, maintain temperature uniformity inside the kiln, and ensure the quality of ceramic products.
In the field of energy, polysilazane ceramic coatings can enhance the weather resistance, corrosion resistance, and wind and sand wear resistance of components such as wind turbine blades and solar thermal conversion devices. For example, wind turbine blades are exposed to outdoor environments for a long time and must withstand wind, sun, sand and dust erosion. Ceramic coatings can protect the blades, extend their service life, and improve the stability and efficiency of wind power generation.
Key process points for preparing polysilazane ceramic coatings
Substrate pretreatment: Before coating with polysilazane, it is necessary to perform sufficient pretreatment on the substrate, such as grinding, cleaning, degreasing, etc., to remove impurities such as oil stains, rust, and oxide layers on the surface of the substrate, making the substrate surface smooth and clean. This can enhance the adhesion between the polysilazane coating layer and the substrate, ensuring the quality of the coating. For example, for metal substrates, sandpaper is commonly used to polish them and then clean them with organic solvents to achieve the desired pre-treatment effect.
Coating process selection: Choose the appropriate coating process based on the shape and size of the substrate, as well as the requirements for coating thickness and uniformity. For large-area and relatively simple shaped flat substrates, immersion coating may be an efficient method that ensures coating uniformity; For components with complex shapes and numerous small structures, the spraying process has more advantages, as it can better cover various parts with the polysilazane solution.
Curing and cracking parameter control: During the curing and high-temperature cracking process, it is necessary to strictly control parameters such as temperature, time, and heating rate. Different polysilazane products may have suitable curing temperature ranges and cracking conditions, and accurate control of these parameters is necessary to ensure that polysilazane is fully cured and smoothly converted into high-quality ceramic coatings. For example, a curing temperature that is too low may result in incomplete curing of the coating, while a cracking temperature or time that is too high may cause defects such as cracking and peeling in the coating.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150K.     
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.