Nano coatings refer to advanced, non-toxic coating technologies using nanomaterials. They are high-tech coatings that provide numerous protective and functional benefits.
Traditional surface coating techniques can often be adapted or slightly modified to incorporate nano-material composite coatings.
In coatings designed for high hardness and wear resistance, the addition of nanoscale components further enhances the hardness and abrasion resistance of the coating while maintaining high toughness.
By integrating nanoparticles into surface coatings, the friction coefficient can be reduced, creating self-lubricating materials or even achieving superlubricity. For example, by incorporating C60, carbon nanotubes, and other advanced materials, new superlubricant materials can be developed. Additionally, nano-materials can significantly improve heat resistance and oxidation resistance. For instance, when a nano Ni-La2O3 coating is deposited on the surface of nickel (Ni), the nano-particles prevent the diffusion of nickel ions and improve the growth mechanism and mechanical properties of the oxide layer.
Nano coatings also enhance the corrosion resistance of the underlying material, providing surface modification and decorative effects. In paints or coatings, adding nanoparticles further boosts protective capabilities, such as resistance to atmospheric conditions, ultraviolet (UV) degradation, and discoloration. Nano coatings can also be applied to building materials like sanitary ware, interior spaces, and appliances to provide antibacterial and cleaning effects.
Nano coatings have a wide range of optical properties. Their optical transmission spectrum extends from ultraviolet (UV) wavelengths to far-infrared (IR) wavelengths. After processing, multi-layered nano coatings can exhibit fluorescence in the visible light range, making them ideal for optical applications like sensors. Nano coatings can be applied to signs, creating luminescent and reflective surfaces. By altering the composition and properties of the nano coatings, effects such as photochromism, thermochromism, and electrochromism can be achieved, creating unique anti-counterfeit and identification features. For example, 80nm yttrium oxide (Y2O3) can serve as an infrared shielding coating, reflecting heat very efficiently. Nano coatings on products like glass can reduce light transmission and thermal transfer, providing insulation properties. Adding nano materials to paints can also enhance fireproofing, heat insulation, and flame retardant effects.
Nano-composite coatings exhibit excellent electromagnetic properties. Coatings made with nano-particles, such as nano-titanium oxide, chromium oxide, iron oxide, and zinc oxide, possess semiconductor properties and can form coatings with effective electrostatic shielding. For example, 80nm barium titanate (BaTiO3) can be used as a high dielectric insulating coating, while 40nm Fe3O4 (magnetite) can be used for magnetic coatings. Multi-layered nano structures can produce giant magnetoresistance effects, which are promising for use in storage systems and readout heads.
The main methods for producing nano coatings include vapor deposition, various spraying techniques (including room temperature spraying, flame spraying, and plasma spraying), and coating processes (such as electroplating and chemical plating).
