Vacuum evaporation coating method

 The use of tantalum, molybdenum, tungsten and other high melting point metal, made of the appropriate shape of the evaporation source, the load on the material to be evaporated, so that air flow through, direct heating of the evaporated material evaporation, or the material to be evaporated into the alumina, beryllium oxide and other indirect heating in the evaporation crucible, which is the resistance heating evaporation method.

Evaporation using resistance heating heater coating machine structure is simple, low cost, reliable, not too high melting point can be used for evaporation coating materials, especially suitable for coating quality requirements are not too high volume of production, So far, the aluminum mirror is still widely used in the production of a resistance heating evaporation process.The drawback is resistance heating: heating the maximum temperature can reach is limited, a shorter heater life fluid. In recent years, in order to improve the life of the heater, domestic and international long life of boron nitride has been synthesized using the conductive ceramic material as the heater. According to Japanese patent reports, can be 20% to 30% of the boron nitride and its phase can be formed by melting of the refractory material to produce crucible, zinc oxide and the surface coated with 62% to 82% of zirconium, and the remaining for the zirconium silicon alloy material.Evaporate plating method of electron beam evaporation source. Water will evaporate into the steel crucible materials, direct electron-beam heating, the evaporation material gasification evaporated film condensation on a substrate surface, the vacuum evaporation coating technology is an important heating methods and development. Electron beam evaporation to overcome the general resistance heating evaporation of many shortcomings, especially for production of high purity thin film materials and film melting point materials.Rely on vacuum electron beam evaporation deposition technique, electron beam evaporation source under different forms, can be divided into the ring gun, straight shots, e-type guns and other types of hollow cathode electron gun.Ring gun is fired by a circular cathode to the electron beam, the focusing and deflection to play in the crucible after the metal evaporation material. Its structure is relatively simple, but the power and efficiency is not high, basically just a laboratory device, the device is currently in production is no longer in use.Axisymmetric gun is a straight line speed gun, electrons from the cathode filament, together into a thin beam, accelerated by the anode coating material to fight manipulation in the crucible melting and evaporation. Straight a few hundred watts of power from the gun to have a few hundred kilowatts, Titanium dioxide and some can be used for vacuum evaporation, and some can be used for vacuum smelting. The drawback is that the gun straight evaporation materials will pollute the gun structure, stability difficult to run, while launching the escape of sodium ions on the filament and other pollution can cause the film, most recently by the West to study, in exit of the electron beam deflection magnetic field settings, and parts of the filament made of a separate exhaust system made of a modified form of the gun straight, not only will the filament completely dry on the membrane fouling, but also help improve the life of the gun.e-type electron gun, the deflection of the electron gun 270 degrees Celsius to overcome the shortcomings of the gun straight, is more used one electron beam evaporation source. e-type electron gun can generate a lot of power density, high melting point to melt the metal, Magnesia resulting in high energy particle evaporation, the film and substrate with a solid, good quality film. Shortcomings that require a higher electron gun vacuum, and requires the use of negative pressure, vacuum chamber requires a check plate, resulting in a device structure of these complex, poor security, easy maintenance, the cost is higher.