Coating technology is an important technology in surface modification engineering. Coating can efficiently achieve the excellent performance of materials and achieve significant economic benefits. Commonly used methods for preparing nanostructured ceramic coatings include plasma spraying, electrophoretic deposition, physical vapor deposition, laser cladding, etc.


1. Plasma spraying
Plasma spraying is divided into atmospheric plasma spraying (APS), supersonic plasma spraying (HVPS), vacuum plasma spraying (VPS), etc. Atmospheric plasma spraying has strong adaptability and can prepare fine coatings by controlling process parameters. Its main disadvantage is that the coating and the substrate are mainly mechanically bonded, and the bonding strength is low, making it difficult to adapt to working conditions such as impact, high stress, and strong fatigue. Supersonic plasma spraying has fast flame flow and high temperature, and is especially suitable for spraying high melting point materials such as ceramics. Compared with other technologies, using plasma spraying to prepare nano-ceramic coatings has the advantages of simple process, wide selection of materials, and high deposition efficiency. The coating prepared by vacuum plasma spraying, which has been widely used in recent years, is denser and has higher bonding strength.