Organic silicon compounds have many unique and excellent physical and chemical properties, which have long attracted widespread attention. The research on polysilazanes with Si-N bond structure has also made significant progress in recent decades. Although the research hotspots of polysilazanes are only in ceramic synthesis, high-temperature resistant silicone rubber and composite materials, its potential application in coatings has gradually become popular. Polysilazanes contain silicon-nitrogen bonds and nitrogen-hydrogen chains. These chemical bonds give it many specific properties. Although people are not very clear about their mechanism of action, these properties play a very important role in coatings.



Polysilazane is widely used in coating varnish formulations, and demonstrates its excellent weather resistance, UV resistance, corrosion resistance, stain resistance, graffiti resistance, scratch resistance, heat resistance, etc. The dry film thickness of polysilazane varnish is usually between 10 nm and 2 μm. Compared with amino alkyd varnish system and two-component polyurethane varnish system, polysilazane varnish has better gloss retention and weather resistance; compared with silicone-modified polyester varnish system, polysilazane varnish has better heat resistance.Aluminum coated with polysilazane coatings remained corrosion-free after 2 400 h of salt spray resistance test (ISO 7253-2001); steel coated with polysilazane coatings remained corrosion-free after 2 400 h of condensation water test (ISO 6270.2-2005). The water contact angle of polysilazane coatings is about 95° and can be maintained for a long time. With the use of appropriate additives, the water contact angle can be increased to more than 120°. This coating has low viscosity, no solvent, no fluorine, and has excellent adhesion to most substrates and has ultra-high hardness (9H+).

When polysilazane is heated to a minimum of 450°C, the polymer will eventually transform into an inorganic ceramic (SiOx), which has extremely high hardness (9H) and ultra-high heat resistance (maximum temperature resistance of 1,800°C). In addition, polysilazane can form a cold blend with most resins that do not chemically react with it, such as thermoplastic acrylic, silicone, and a mixture of organic polysilazane and inorganic polysilazane.