What are the applications of plasma technology in surface technology?
(1) Sputtering deposition: Sputtering uses high-speed ions to hit a solid target, so that surface molecules are sputtered and shot onto the substrate to form a thin film. The initial kinetic energy of the sputtered ions is about 100eV. The commonly used plasma gas is argon, which is of appropriate quality and has no chemical reaction.
(2) Plasma-assisted deposition: The chemical reaction of vapor phase chemical deposition is carried out on a high-temperature substrate, so that the gas precursor can obtain sufficient energy to react.
(3) Plasma polymerization: The simplest coating technology for polymer or plastic film is to coat it in a solvent and then coat it on the substrate. The plasma polymerization coating method excites molecular monomers into plasma, which forms a uniformly dense polymer after chemical reaction and coats it on the substrate. Since the substrate is impacted by the plasma, its adhesion is also very strong.
(4) Plasma etching: wet alkaline etching, which is the simplest and cheapest method. Its disadvantage is that alkaline etching has crystal plane orientation and will cause down-etching problems.
(5) Plasma spray coating: The metal components operating at high temperatures must be covered with ceramics to prevent high temperature corrosion.
4. What are the heating methods of vapor deposition? What are the characteristics of each?
Heating methods are divided into:
(1) Resistance heating (2) Induction heating (3) Electron beam heating (4) Laser heating (5) Arc heating
Features of each:
(1) Resistance heating: This is the simplest heating method. Its advantages are cheap equipment and easy operation.
(2) Induction heating: good heating efficiency, rapid heating, and large capacity heating.
(3) Electron beam heating: This heating method is to focus thousands of eV high-energy electrons through a magnetic field and directly hit the evaporate to heat, and the temperature can be as high as 30,000C. There are two sources of electrons: thermionics produced by high-temperature metals, and the other source of electrons is the discharge of the hollow cathode.
(4) Laser heating: The laser beam can be optically focused on the evaporation source, generating a local instantaneous high temperature to make it escape. The pulsed ruby ​​laser was first used, and then the ultraviolet excimer laser was developed. The advantage of ultraviolet light is that the energy of each photon is much higher than that of infrared light. Therefore, the power density of excimer laser is very high, and the function of heating and evaporation is similar to that of electron beam. It is often used to coat complex compounds, and the quality of the coating is very good. It is basically different from the process of electron beam heating or sputtering. Excimer lasers are separated from fine particles, while the latter is based on molecules. Form break away.