Example : Ceramic coating

Disperse silicon carbide, silicon nitride or their mixture in a solution composed of polysilazane and aromatic hydrocarbon solvent to make paint. This coating can provide protective ceramic coatings for carbon/carbon composites, graphite and other carbon-containing materials. For example, a graphite test piece with a size of 3.8 cm×2.5 cm×0.5 cm is polished to a smooth surface, cleaned, and dried in a vacuum, and the paint is fully brushed, air-dried, and dried at 100°C for 5 min to about 10°C Heat to 150°C at a rate of /min, and keep it at 150°C for 15-30 minutes, and then allow it to cool to room temperature. Then apply another coat of the paint on the test piece, heat it to about 175~186℃, keep it at this temperature for at least 15 minutes, and cool it down. The thickness of the coating is about 0.08~0.10 mm. Heat the painted test piece to 650~700℃, keep it at this temperature for 15~30 minutes, and then cool it to room temperature to make the coating pyrolyze into a ceramic coating. Heat the painted sample to 850℃ for 5~10 min. The effectiveness of the resulting ceramic coating in protecting the graphite surface from thermal degradation can be confirmed by the following test: Heat it to 600℃ for 1 h, and calculate the number of dents on the surface. The average number of dents per square inch of the 3 painted samples is only 8 to 86, but the unpainted graphite sample per square The average number of dents in inches is 590 to 630.

Example : Anti-rust paint

The deep-drawn steel sheet is immersed in a 20% concentration of perhydropolysilazane (number-average molecular weight 150~150 000) solution for coating, deep-drawing in air at a rate of 0.3 m/min, and drying at room temperature After about 30 minutes, place the painted steel plate in an air furnace at 700°C for 10 hours at a heating and cooling rate of 3°C/min. The test results found that the painted steel plate had no oxide layer or rust.

Example : Car body and wheel coating

The coating uses perhydropolysilazane or organopolysilazane with a number average relative molecular mass of 150 to 150,000. The coating formula is 35%~40% polysilazane, 0.5%~1% polyacrylate and less than 2.0% flow control aid. The solvent is butyl acetate. The aluminum parts are sprayed with a spray gun, and the topcoat is acrylic powder paint or solvent-based or water-based varnish. Bake this aluminum piece at 170°C for 20 min. The thickness of the coating is 5 μm, and the surface roughness is 0.09 μm.
Brake dust test: Suspend the brake dust in water, then apply it to the sample plate, store the sample plate at 160°C for 2 hours, then rinse it with water, wipe it lightly, and then evaluate it. The evaluation value is level 1. It can be seen that the coating can prevent "staining" of brake powder, has good scratch resistance and corrosion resistance, and its water contact angle is 108°.