What causes blue, yellow and black aluminum plating in vacuum coating machines?

Blue color is usually due to oxidation (it solidifies immediately after plating); black color is generally due to premature oxidation; yellow color is due to brown, I don’t know if you are referring to it. What about the problem? There are many situations that can cause brown streaks to appear on the surface of the film. If you are referring to this problem, I can help you find various causes and corresponding solutions. Also, when you raise the issue of fogging workpieces, do you also refer to aluminized workpieces? Follow-up question: It is ordinary evaporation, which does not require any color, as long as the workpiece is bright, and it is in a vacuum state. The cause of the blue color should be caused by the sublimation of the tungsten wire due to excessive voltage. The oxidation problem is basically very small. Yes Vacuum coating, what I want to ask is the comprehensive and fundamental reason for the above problem. Answer: What I know below for those with little talent and knowledge: (color problem) ① Solution to low vacuum degree: clean the aluminum feeding, evaporation device, and cooling in the vacuum chamber system, unwinding, winding device and guide roller; check the vacuum system; reduce the ambient humidity. ②Solution to the film releasing gas: Pre-dry the film; extend the vacuuming time. ③Solutions to excessive aluminum spraying: increase vehicle speed; reduce evaporation boat current; reduce aluminum feeding speed. ④ Solution to impurities in the evaporation boat: Clean the evaporation boat and heat shielding plate. ⑤Solution to the aging of the evaporation boat: Replace the evaporation boat. Supplement: I don’t know if the above is helpful. I don't know about the fogging problem of aluminum plating, sorry. Follow-up question: Sorry, I didn’t mean that you are inexperienced - -#, I meant that the reasons for yellowing are: 1. The vacuum is too low; extending the vacuuming time; 2. There are other sources of outgassing during coating that affect the coating effect. , such as fixtures or tapes 3. The coating time is too long; too much aluminum spraying 4. The coating current is too high 5. The film releases gas 6. The protective film is too long and too thick. This is just a single and comprehensive answer - -# Answer : Haha, I am making fun of myself...