Definition of coated glass ：
Coated glass is a glass deep-processing product that coats one or more layers of metal, alloy or metal compound film on the surface of glass, or migrates metal ions to the surface layer of glass to change the optical properties of glass and meet certain specific requirements.
The main production method of coated glass：
1,Chemical vapor deposition：
Chemical vapour deposition (CVD) is a process technology that supplies one or several compounds or elemental gases containing thin film elements to the substrate, and uses the gas phase reaction to react and deposit the required solid film on the surface of the substrate, which has become the main preparation technology for the production of coated glass.
The on-line CVD coating technology is the CVD process technology for the continuous deposition of compound thin films in the production process of float glass, which is currently the most advanced coated glass production technology in the world. It is based on clean, high-speed traction (8-15m/min), high-temperature (600°C) float glass as the substrate for deposition. In other words, before the film is deposited, the glass substrate is about to leave the tin bath but has not yet entered the annealing kiln and has not been treated for purification. It was the first in China to use the online CVD method to continuously deposit Sn02 thin films, and in China, it was the first to use this method to produce siliceous coated glass. At present, China has basically mastered the online CVD coating technology, which can stably produce siliceous coated glass, online Low-E glass and online self-cleaning glass.
Solid powder spraying method：
Spraying coating technology is a process method that sprays one or more atomized particles or organometallic salt powder of one or more reactive gases or organometallic salt compound solutions on the surface of hot glass and thermally decomposes them into films. The solid powder coating method was originally applied to the float production line by Ford Motor Company in the early 80s of the 20th century. The coating zone of the solid powder coating method is generally set up after the transition roller of the float glass production line and before the annealing kiln, which is what we usually call the A0 zone of the annealing kiln.
The basic principle is to spray one or more components of organometallic salt powder on the surface of hot glass through a special spray gun with the help of a compressed gas carrier, and use the high-temperature thermal decomposition of organometallic salts to form a layer of metal oxide film on the surface of the glass, and the reaction exhaust gas, unreacted solid powder and substances that participate in the reaction but are not filmed on the glass surface are discharged out of the kiln in time through the dust collection equipment to keep the glass surface and the kiln clean. The coating unit equipment is mainly composed of servo reciprocating automatic spraying machine, feeder, vibrating feeder and dust collection system. Among them, the servo reciprocating automatic spraying machine is equipped with a spray gun, and the spray gun is an important device for spraying solid powder on the surface of hot glass to form a film, and the spray gun structure, weight, spraying angle and other factors can have a great impact on the spraying effect.
Vacuum evaporation：
Vacuum evaporation coating method (referred to as vacuum evaporation method, Vacuum Evaporation) refers to the method of using high temperature heating evaporation materials (metal alloys or metal oxides) to a certain temperature under certain vacuum conditions, so that atoms or molecules can vaporize and escape from the surface to form a vapor flow, and fly to the surface of the glass substrate to condense to form a solid film.
Since the main physical process of vacuum evaporation forging is produced by heating and evaporating materials, it is also called thermal evaporation method. As a key component of the evaporation unit, most evaporation materials require evaporation at a high temperature of 1000-2000°C. Vacuum evaporation method can be divided into resistance method, electron beam evaporation method, high-frequency induction method and laser evaporation method according to different evaporation sources. At present, the vacuum evaporation method is used to produce coated glass, and the production of coated glass is in batch mode.
Vacuum magnetron sputtering method：
The production methods of magnetron sputtering method include batch and continuous production method, of which continuous production method can be divided into two types: horizontal and vertical continuous production. Among them, the horizontal continuous production method is a production method in which the glass substrate completes all the processing technology in the horizontal conveying process, and the double-end machine with 3 sputtering chambers is used.
The advantages of magnetron sputtering coating are mainly as follows:
the core does not require the area and shape of the target, and can realize large-area coating, and the film uniformity is good, the film thickness is controllable, and the sputtering process repeatability is good;
the available film materials are extensive, as long as any material that can be made into the target can be sputtered, so the film of most materials can be prepared, including alloys and compounds, etc.;
the adhesion between the film and the substrate is strong, the film layer is high purity and dense;
(4) the film forming speed is fast, and the production efficiency is high.
Summary Since the development of coated glass preparation technology in the 70s of the 20th century, a relatively mature and complete technical system has been formed.