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frequently asked questions

Update:25-03-2020
Summary:
  1. What is the reason for the difference of adsorption between vacuum evaporation and vacuum splashing?

 

Sputtering is a strong adsorption of positive and negative electrodes, so the adsorption of sputtering is more uniform, the density is greater, the hardness is greater, and the price of sputtering is 10% - 20% higher than that of evaporation.Plasma Coating Machine Manufacturers

 

  1. Why can vacuum coating be made into different colors, and seven colors?

 

Because after the vacuum evaporation, a layer of UV varnish will be sprayed, and different colors can be made on this layer of paint. Evaporation plating can be made into seven colors by plating some silicides, but it is relatively thin, which can be seen in the near and not obvious in the far; sputtering can be made into seven colors by reactive plating with CSI, Co, Si and other substances, or it can be made into many colors by low-temperature multi-layer coating of different colors. But the water electroplate's general is the metal natural color, must present other colors needs to apply the UV topcoat and then the UV irradiation.

 

  1. Why is vacuum coating semi transparent and non conducting?

 

It is not completely non-conductive. The discontinuous metals or metal compounds in the film state have conductivity, but the conductivity is different. However, when a metal or a metal compound is in a film state, its corresponding physical properties will be different. Among the conventional coating materials, for example, silver is the metal with the best silver white effect and conductivity, but when its thickness is less than 5 nm, it is non-conductive; the silver white effect and conductivity of aluminum are slightly worse than that of silver, but when its thickness is 0.9 nm, it has conductivity. Why is that? That's because the continuity of silver molecules is not as good as that of aluminum, so the conductivity of silver molecules is poor under the relative film thickness. In fact, we use the principle of poor molecular continuity of some metals to control its thickness in a certain range, so that it has a silver white appearance and large resistance. It can be seen that the effect of metal nonconductive film is directly related to its film thickness. Only under the corresponding film thickness, the corresponding stable silver white non conducting film can be obtained. As mentioned above, when the silver with the best silver white effect and conductivity is less than 5 nm thick, it is non-conductive. So, can silver be used as the non-conductive metal film we need? The answer is No. Because the thickness of silver below 5 nm is basically transparent and colorless. Although it is not conductive, it cannot have the effect of silver white reflective film at the same time. Aluminum, too. Therefore, we need a kind of resistance metal material which can be plated with silver white metallic luster. We use tin or indium and indium tin alloy with purity over 99.99%. Tin with thickness less than 30 nm has poor continuity, but it can obtain silvery white metallic luster and high resistance. Indium is the same, but the silver white reflection rate of indium is better than the appearance of tin, because the price is higher, we use indium tin alloy, so we can get both non-conductive film and white and bright reflection metal effect! Indium tin non-conductive films are all translucent, so we require the substrate to be transparent or black. Because indium tin plating starts to dissolve at 250 ℃, the evaporation temperature is relatively low, so the current and time for heating melting and evaporation are relatively low.

 

  1. Why does aluminum plating of vacuum coating not conduct electricity?

 

Because the coating has three layers in total, the UV light oil at the outermost layer plays the role of curing wear-resistant insulation after UV irradiation, but once the film is damaged, it conducts electricity.

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