The research time of nano-coatings is not too long, and there are many problems wait to be deeply studied and discussed.
1. Coating thickness and adhesion problems
The reference thickness of the conventional coating is generally about 2 ~ 6 μm on the single side. But the nano-coating is different. It requires that the material particles must be nano-scale, and the coating must be densely bonded with the substrate to play the structural and functional role.
2. Preparation of nanostructured particle material for thermal spraying
For coating technology, the obstacle to the development of thermal spray nano-coating technology is that the nano-powders cannot be directly used for thermal spraying. Nano-particles must be re-formed into micron-sized particles (feeding materials) by the granulating technology before they can be sprayed on substrates with thermal spraying technology. In United States, technicians use atmospheric plasma spraying technology to deposit zirconium oxide nano-coating after nanometer was changed to micrometers. The determination of microstructure and phase composition reveals that coatings and substrates are well combined. If adopts advanced closed field unbalanced magnetron sputtering method, there are too many working procedures, and direct thermal spraying of nano-ceramic coating can hardly ensure the stable dispersion of nano-ceramic particles. Therefore, the mechanism and its control measures of stable dispersion of nano-ceramic slurry must be studied.
2. Too many procedures and high costs
For example, nano-WC/Co coating materials and coating technologies jointly developed by Rutgers University and Naval Research Institute also have the problems of complicated processes and high costs.
Nano-coatings and its preparation techniques are developing with the development of nano-materials. On the basis of the continuous progress in the preparation of nanomaterials and the deepening of basic theoretical research, the nanometer functional coatings will have faster and more comprehensive development in the near furure, and the coating methods will continue to be innovated and improved, also the applications will expand to more fields. Besides the large-scale product group and enterprise group will be rapidly formed, which will not only play an irreplaceable role in the high-tech field, but also bring vitality and energy to traditional industries.