As a method to strengthen and modify the solid surface, coatings have been widely used in mechanical, electronic, chemical, aerospace and other fields. With the development of science and technology, materials are required to be serviced under special conditions, such as ultra-high temperature, ultra-low temperature, ultra-high pressure, high vacuum, strong redox or corrosive environments with the presence of radiation, sound absorption signal shielding, bearing load, etc, which puts forward higher requirements for traditional coating.
Researches showed that when a certain geometrical size (granularity, diameter, film thickness, grain size) of a certain phase in a material is nanoscaled, the characteristics of the material tend to mutation. Due to the affects of surface effects, small size effects and quantum effects, the physical properties and mechanical properties of nanomaterials, such as high strength, high toughness, high specific heat, high thermal expansion rate, high electrical conductivity etc. are different from macro materials. And these properties have become an important research field at the forefront of the development of science and technology in the 21st century. The nanocoatings that prepared by nano-materials and surface coating technology is conducive to expand the application of nano-materials and further improve the coating technology.
Nano-coatings can be prepared by traditional materials, powder particles or fibers. The nano-coating is one of the hot topics in nanomaterials science research in recent years. The main researches are focused on functional coatings, including general coating, fiber coating and particle coating on the surface of traditional materials.
The properties of nano-coating are reflected in the following aspects:
(1) Nanophase can increase the hardness and wear resistance of the coating, and help maintain high toughness
(2) Nanocoating can improve the material's high temperature resistance and oxidation resistance
(3) Nanocoating can improve the anti-corrosion properties of the substrate to achieve the purpose of surface modification and decoration
(4) Nanophase help reduce the friction coefficient to form R lubricant material
(5) Nanocoatings have widely varying optical properties and excellent electromagnetic properties