Application of Vapor Deposition Technology in Surface Treatment
Vapor deposition technology refers to a new type of coating technology that deposits gaseous substances containing sedimentary elements onto the surface of materials through physical or chemical methods to form a thin film. According to the different principles of sedimentary processes, vapor deposition techniques can be divided into two categories: physical vapor deposition (PVD) and chemical vapor deposition (CVD).
1、Physical vapor deposition
Physical vapor deposition (PVD) refers to the technique of using physical methods to vaporize a material into atoms, molecules, or ions under vacuum conditions, and depositing a thin film on the surface of the material through a vapor phase process. Physical deposition technology mainly includes three basic methods: vacuum evaporation plating, sputtering plating, and ion plating.
Vacuum evaporation plating is a method of evaporating film-forming materials to evaporate or sublimate and deposit them onto the surface of the workpiece to form a thin film. According to the different melting points of evaporated materials, there are various heating methods such as resistance heating, electron beam heating, laser heating, etc. The characteristic of vacuum evaporation plating is that the equipment, process, and operation are simple, but due to the low kinetic energy of vaporized particles, the adhesion between the coating and the substrate is weak, and the coating is relatively loose, resulting in low impact resistance and wear resistance.
Sputtering plating is a method of ionizing argon gas through glow discharge under vacuum, and the generated argon ions accelerate the bombardment of the cathode under the action of an electric field. The sputtered particles deposit on the surface of the workpiece to form a film; Its advantages include high kinetic energy of gasification particles, wide range of applicable materials (including substrate materials and coating materials), good plating ability, but slow deposition speed and expensive equipment.
Ion plating is a method of using gas discharge technology under vacuum to ionize the evaporated atoms into ions, which are then deposited onto the surface of the workpiece along with a large number of high-energy neutral particles generated at the same time to form a film. Its characteristics are high coating quality, strong adhesion, good uniform plating ability, and fast deposition speed, but it has disadvantages such as complex equipment and high cost.
Physical vapor deposition has a wide range of applicable matrix and film materials; Simple process, material saving, and pollution-free; The obtained film has advantages such as strong adhesion to the substrate, uniform film thickness, density, and fewer pinholes. It has been widely used in the fields of machinery, aerospace, electronics, optics, and light industry to prepare wear-resistant, corrosion-resistant, heat-resistant, conductive, insulating, optical, magnetic, piezoelectric, and smooth superconducting thin films.
2、Chemical vapor deposition
Chemical vapor deposition (CVD) refers to the method of forming a metal or compound film on the surface of a substrate by the interaction between a mixed gas and the substrate surface at a certain temperature.
The characteristics of chemical vapor deposition are: there are many types of deposits, which can be divided into deposited metals, semiconductor elements, carbides, nitrides, borides, etc; And can control the composition and crystal form of the film within a large range; Capable of evenly coating parts with complex geometric shapes; Fast deposition speed, dense film layer, and firm bonding with the substrate; Easy to achieve mass production.
Due to its excellent wear resistance, corrosion resistance, heat resistance, electrical, optical and other special properties, chemical vapor deposition coatings have been widely used in industrial fields such as mechanical manufacturing, aerospace, transportation, and coal chemical industry.