By Dr.Zhang from Nanjing Normal University | 16 July 2020 | 0 Comments
Wide application of MAX phase ceramic materials
Application of Spraying Method in MAX Phase Coating
Thermal spraying
Thermal spraying is a technology that uses high temperature heat source to heat the sprayed material to the state of melting or melting, and then sprays it to the surface of the substrate through high-speed airflow to form a spraying coating. There are many methods of thermal spraying, which can be divided into four kinds according to the different heat sources: flame spraying, arc spraying, plasma spraying and special spraying. At present, plasma spraying is the main method to prepare ceramic coatings.
Supersonic flame spraying technology has been developed by flame spraying. It uses the mixed combustion of fuel and combustion-supporting gas to make the gas flow expand sharply when heated, shrink first and then expand after the nozzle, and the gas velocity reaches supersonic speed. At the same time, when heated, the powder becomes particles and collides with the matrix to form a coating.
Cold Spraying Method
Compared with traditional thermal spraying, cold spraying has unique advantages, but there are also some limitations and shortcomings. Cold spraying does not require too high temperature in the spraying process, so phase transformation, decomposition and some chemical reactions of spraying particles can be avoided in the spraying process: some materials are sensitive to temperature and cannot withstand high temperature, so cold spraying can be used to realize the preparation of coatings. Cold spraying process has no thermal effect on the matrix, no pollution to the environment, powder can also be recycled, coating deposition efficiency is relatively high, can achieve good conductivity and thermal conductivity of the coating. However, due to the dependence of cold spraying technology on high-speed impact plastic deformation, hard brittle materials such as ceramics cannot prepare thicker coatings. In the preparation of high quality coatings, the properties of sprayed particles and matrix depend to a great extent.
When ceramic particles collide with matrix at high speed, the sprayed particles break into smaller particles or fragments instead of plastic deformation, forming a coating embedded by nano-scale fragments. Due to the mechanical interlock between particles, the impact of subsequent spraying particles may cause erosion of the coating, and may also make the coating more compact, so as to achieve the effect of coating densification. Through many experiments, the results show that if the sprayed particles are nano-agglomerated structure, it will be easier to achieve single layer deposition of ceramics. Nano-agglomerated powders are necessary for cold spraying of ceramic materials, but they are not sufficient because the effect of cold spraying is also related to agglomeration mode and degree.
Summary and Prospect
The ternary layered compound MAX phase is a new type of structural-functional integrated ceramic material, which has a wide application prospect. At present, the study of MAX phase needs deeper research and extensive experimental verification in the application field. The study of MAX phase should focus on the synthesis of new phase and the industrial application of discovered phase. The recognition of MAX phase coatings prepared by spraying technology is a process of continuous exploration and gradual deepening. Although some progress has been made, there are still many shortcomings. More research is needed to improve and solve these shortcomings. It can be believed that the ternary layered compound MAX phase will be widely used in industry due to its unique advantages after a period of efforts.
TRUNNANO (Luoyang Trunnano Tech Co., Ltd ) is a professional new nano material manufacturer with over 12 years experience in chemical products research and development. If you are looking for high quality new nano material, please feel free to contact us and send an inquiry.
Thermal spraying
Thermal spraying is a technology that uses high temperature heat source to heat the sprayed material to the state of melting or melting, and then sprays it to the surface of the substrate through high-speed airflow to form a spraying coating. There are many methods of thermal spraying, which can be divided into four kinds according to the different heat sources: flame spraying, arc spraying, plasma spraying and special spraying. At present, plasma spraying is the main method to prepare ceramic coatings.
Supersonic flame spraying technology has been developed by flame spraying. It uses the mixed combustion of fuel and combustion-supporting gas to make the gas flow expand sharply when heated, shrink first and then expand after the nozzle, and the gas velocity reaches supersonic speed. At the same time, when heated, the powder becomes particles and collides with the matrix to form a coating.
Cold Spraying Method
Compared with traditional thermal spraying, cold spraying has unique advantages, but there are also some limitations and shortcomings. Cold spraying does not require too high temperature in the spraying process, so phase transformation, decomposition and some chemical reactions of spraying particles can be avoided in the spraying process: some materials are sensitive to temperature and cannot withstand high temperature, so cold spraying can be used to realize the preparation of coatings. Cold spraying process has no thermal effect on the matrix, no pollution to the environment, powder can also be recycled, coating deposition efficiency is relatively high, can achieve good conductivity and thermal conductivity of the coating. However, due to the dependence of cold spraying technology on high-speed impact plastic deformation, hard brittle materials such as ceramics cannot prepare thicker coatings. In the preparation of high quality coatings, the properties of sprayed particles and matrix depend to a great extent.
When ceramic particles collide with matrix at high speed, the sprayed particles break into smaller particles or fragments instead of plastic deformation, forming a coating embedded by nano-scale fragments. Due to the mechanical interlock between particles, the impact of subsequent spraying particles may cause erosion of the coating, and may also make the coating more compact, so as to achieve the effect of coating densification. Through many experiments, the results show that if the sprayed particles are nano-agglomerated structure, it will be easier to achieve single layer deposition of ceramics. Nano-agglomerated powders are necessary for cold spraying of ceramic materials, but they are not sufficient because the effect of cold spraying is also related to agglomeration mode and degree.
Summary and Prospect
The ternary layered compound MAX phase is a new type of structural-functional integrated ceramic material, which has a wide application prospect. At present, the study of MAX phase needs deeper research and extensive experimental verification in the application field. The study of MAX phase should focus on the synthesis of new phase and the industrial application of discovered phase. The recognition of MAX phase coatings prepared by spraying technology is a process of continuous exploration and gradual deepening. Although some progress has been made, there are still many shortcomings. More research is needed to improve and solve these shortcomings. It can be believed that the ternary layered compound MAX phase will be widely used in industry due to its unique advantages after a period of efforts.
TRUNNANO (Luoyang Trunnano Tech Co., Ltd ) is a professional new nano material manufacturer with over 12 years experience in chemical products research and development. If you are looking for high quality new nano material, please feel free to contact us and send an inquiry.
Leave a Reply
Your email address will not be published.Required fields are marked. *