Common problems and treatment in the process of vacuum coating



In addition, there are black spots on the electroplating aluminum layer, common symptoms: black spots on the surface of the coating, or water stains on the edge of the workpiece. Peeling off the surface coating, you can see that the black spots are actually a layer of oxide film formed on the surface of the electroplating aluminum layer, and the oxide film is black.
The general electroplating UV process of the workpiece is divided into three layers. The first layer is a closed UV layer in contact with the substrate, that is, the primer layer, the second layer is an electroplating layer, commonly known as aluminum plating, and the third layer is a protective layer, that is, UV surface coating.
The current situation is that the aluminum plating layer is oxidized, and the resulting aluminum oxide shows black spots, which affects the overall aesthetics of the workpiece. The fundamental problem is that the workpiece has not been closed in time after the completion of electroplating, resulting in the environment. Water and oxygen have enough time to penetrate the surface coating and make the coating oxidized.
If the topcoat coating is not sufficient in the curing energy or curing effect is not complete, it will affect the density of the film, there is a certain oxygen and moisture through the rate, especially with the change of room temperature and humidity and obvious change, in the high temperature and high humidity environment, water is particularly easy to penetrate the past. This requires the workpiece to be packaged in time after completion to prevent the erosion of moisture and oxygen in time. At the same time, the coating is too thin is also one of the reasons for the easy oxidation of the coating. Appropriate increase of the thickness of the coating can not only improve the aesthetics of the workpiece, but also effectively prevent the coating from being oxidized too quickly in harsh environments.
This problem has been repeated, irregular and uncertain. As long as the conditions are suitable, this problem is easy to occur. It is necessary to fundamentally solve this problem, improve the curing compactness of the top coating, enhance its ability to resist oxygen and moisture erosion, and achieve perfect protection effect. Secondly, the workpiece should be sealed and protected as soon as possible after completion to minimize its storage in high temperature and high humidity environment, finally, under the premise of process and cost conditions, the appropriate increase in the thickness of the coating can also effectively prevent the problem of black spots after the coating is placed for a long time. The occurrence of black spots in the oxidation of the coating is a slow change process for a long time, and the key to solve the problem of black spots is to take appropriate methods to prevent the coating from being oxidized prematurely.