Thermal spraying technology is actually the use of heat to melt the coating material onto the substrate material to be processed. Due to the wide range of coating materials, fast deposition speed, high flexibility, easy automatic processing, strong adaptability and other advantages, so slowly The technology has been widely used.
Statistics show that there are more than 5,000 parts and components required for thermal spraying for an advanced foreign aeroengine, and thermal barrier coating has become one of the key technologies in the manufacture of high-performance aeroengines; in addition, according to foreign countries’ high-performance ceramic coating applications According to the statistics report, thermal spraying ceramic coatings accounted for two-thirds of the high-performance ceramic preparation market in North America, which is basically consistent with domestic reports that the output value of thermal spraying is about one-third of the total output value of surface technology , Indicating that thermal spraying technology has become one of the important surface engineering technologies.
The spraying material is melted by heat energy, and then atomized by the high-speed airflow, and the particles hit the surface of the substrate driven by the high-speed airflow, and form a coating with a certain function after condensation, that is, thermal spraying technology.
Thermal spraying gave birth to different methods and technologies in different ages:
1910: Wire flame spraying technology; wire flame spraying is widely used in the preparation of corrosion-resistant and wear-resistant coatings on the surfaces of mechanical parts, chemical containers and rollers. After making appropriate changes to the spray gun nozzle part, it can also be used to spray plastic powder. 1920s: Electric arc wire spraying technology, with the following characteristics:
(1) Spray special and aluminum coatings on steel components to provide long-term protection to the components.
(2) Spray aluminum on steel parts to prevent high temperature oxidation.
(3) Spray stainless steel or other wear-resistant metals on steel parts for wear-resistant corrosion protection.
(4) Coating carbon steel, bronze and other materials on mechanical parts for repairing parts.
(5) Spray shielding coating etc. on plastic products.
(6) Use arc spraying aluminum or spray casting to produce composite copper plates.
Explosive spraying and plasma spraying technology in the 1950s: The plasma arc flame has a high temperature and is suitable for spraying high melting point materials. The coating density can reach 85-98%, the bonding strength is as high as 35-70Mpa, and the spraying quality is much better than that of the flame sprayed coating. Mainly used:
(1) Wear-resistant and anti-wear coating;
(2) Corrosion resistant coating;
(3) Anti-high temperature oxidation, resistance to high temperature air flow erosion, and thermal barrier coating;
(4) Manufacturing metal and ceramic high-melting point composite materials.
