The following are several common methods to improve coating hardness through post-treatment processes:
heat treatment
Low temperature annealing: For some organic coatings, such as epoxy resin coatings, polyurethane coatings, etc., low-temperature annealing treatment is carried out after curing, and the temperature is usually controlled within a range slightly higher than the curing temperature of the coating but lower than the decomposition temperature of the coating material, generally between 100 ℃ and 200 ℃. For example, annealing the epoxy resin coating at 150 ℃ for 2-4 hours after curing can further relax and rearrange the molecular chains inside the coating, promote further cross-linking between incomplete functional groups, improve the cross-linking network structure of the coating, and thus increase the hardness of the coating, resulting in an increase of about 10-20 units in Rockwell hardness (HR).
High temperature sintering: suitable for inorganic coatings such as ceramic coatings and metal ceramic coatings. Taking alumina ceramic coating as an example, after being prepared by thermal spraying and other processes, it is placed in a high-temperature furnace for sintering treatment. The sintering temperature can be as high as 1000 ℃ -1600 ℃, and the time is adjusted according to factors such as coating thickness, usually 1-5 hours. During the high-temperature sintering process, further diffusion and fusion occur between ceramic particles in the coating, eliminating pores between particles and forming a denser structure, greatly enhancing the hardness of the coating. The Vickers hardness (HV) can be increased from the original 1000-1200 to 1500-2000 or even higher.
Aging treatment: Aging treatment is an effective post-treatment method for metal coatings, such as aluminum alloy coatings, nickel based alloy coatings, etc. Keeping the coating at a certain temperature (usually between 150 ℃ and 500 ℃) for a long time, such as 10-50 hours, allows the alloy elements in the coating to fully diffuse and precipitate, forming strengthening phases. These strengthening phases can be dispersed in the coating matrix, hindering dislocation movement and thereby improving the hardness and strength of the coating. The Brinell hardness (HB) can be increased by about 20% -50%.
Surface chemical treatment
Silanization treatment: commonly used for surface modification of organic coatings and some inorganic coatings. For example, immerse the coated component in a solution containing silane coupling agent (such as gamma aminopropyltriethoxysilane, etc.), take it out and dry it after a certain period of time (usually 10-60 minutes), and then cure it at an appropriate temperature (such as 80 ℃ -120 ℃) for 1-2 hours. Silane coupling agent molecules will undergo chemical reactions with hydroxyl and other active groups on the surface of the coating, forming a hard protective film rich in siloxane bonds on the surface, improving the hardness and wear resistance of the coating surface. For organic coatings with originally low hardness, their pencil hardness can be increased from 2H to 3H-4H.
Phosphating treatment: mainly applied to organic coatings on metal coatings and some metal substrates. Taking the zinc based phosphating treatment on the surface of steel as an example, steel components are placed in a phosphating solution containing zinc dihydrogen phosphate, zinc nitrate, and other components. Under certain temperature (usually 40 ℃ -60 ℃) and time (10-30 minutes) conditions, a phosphating film is formed on the surface of the steel. This film is composed of compounds such as zinc phosphate, which, when combined with the coating, can enhance the adhesion of the coating to the substrate and improve the overall hardness of the coating, significantly enhancing the scratch resistance of the coating. The Vickers hardness (HV) can be increased by about 50-100.
Chemical plating treatment: A layer of metal or alloy can be deposited on the surface of the coating to enhance its hardness. For example, chemical nickel plating treatment is carried out on the surface of plastic coatings. Firstly, the plastic coating is pre treated (such as roughening, sensitization, activation, etc.), and then it is placed in a chemical plating solution containing nickel salts (such as nickel sulfate), reducing agents (such as sodium hypophosphite), and other components. Under suitable temperature (80 ℃ -90 ℃) and pH (4-6) conditions, nickel will deposit on the surface of the coating to form a nickel plating layer, which is tightly bonded to the coating, greatly improving the hardness of the coating. The Rockwell hardness (HR) can be increased from the original 30-40 to around 60-70.
Physical processing
Ion implantation: Through ion implantation equipment, high hardness ions (such as nitrogen ions, titanium ions, boron ions, etc.) are accelerated and injected onto the surface of the coating. For example, nitrogen ions can be injected into silicon nitride coatings at energies between 10-100keV and doses ranging from 1 × 10 ¹⁵ -1 × 10 ¹⁷ ions/cm ². The injected ions will change the chemical composition and crystal structure of the coating surface, forming new compound phases or lattice distortions, thereby increasing the surface hardness. The Vickers hardness (HV) can be increased by about 30% -80%, and the wear resistance, corrosion resistance and other properties of the coating can be improved.
Laser processing: Using high-energy density laser beams to irradiate the surface of coatings. For example, for metal coatings, pulsed laser is used with an energy density set between 1-10 J/cm ², and the laser pulse width is in the nanosecond to microsecond range. After irradiation, the coating surface will quickly melt and then solidify, forming a fine grain structure. At the same time, some new strengthening phases may also be generated, significantly improving the hardness of the coating. The Brinell hardness (HB) can be increased by about 20% to 60%, and this treatment method can make the coating surface smoother and more polished, which is conducive to improving the comprehensive performance of the coating.
Shot peening strengthening: suitable for metal coatings and some coatings with certain toughness. Spray small pellets (such as steel balls, ceramic balls, etc.) onto the surface of the coating at a certain speed and angle. The impact of the pellets on the coating will cause plastic deformation, forming a residual compressive stress layer on the surface of the coating. At the same time, refine the grain structure of the coating surface, improve the hardness and fatigue resistance of the coating. For example, by using steel balls with a diameter of 0.2-0.5mm and shot blasting aluminum alloy coatings at a speed of 20-50m/s, the Brinell hardness (HB) of the coating can be increased by about 10-20%, and the service life of the coating under alternating loads can be effectively extended.

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