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The principle and characteristics of mechanical galvanizing process
Mechanical galvanizing is a high-tech process technology developed in the late 20th century based on the traditional electroplating technology. In this process, the plated objects are processed on a special mechanical galvanizing machine, and are coated with zinc by high-frequency mechanical stirring, so as to obtain a hard, smooth and glossy zinc coating.
The mechanical galvanizing process mainly includes the following steps: degreasing, pickling, passivation, pre-galvanizing treatment, mechanical stir-dipping, drying and post-galvanizing treatment.
1. Degreasing: Degreasing is to clean the surface of objects with specialized degreasing agent, in order to remove oil, dust, dirt, etc., and lay the foundation for the later in-depth treatments of objects.
2. Pickling: Pickling is to clean the surface of objects by spraying pickling solution, rinsing and other processes, in order to remove rust, scale and other impurities, so as to ensure general corrosion resistance of the processed objects.
3. Passivation: Passivation is to make use of passivation solution to form a dense oxide film on the surface of objects, so as to improve the corrosion resistance of processed objects.
4. Pre-galvanizing treatment: Pre-galvanizing treatment is to clean the surface of objects after passivation, and then to coat with a layer of protective film, in order to avoid the possibility of direct contact between zinc and processed objects, so as to ensure cleaning in the later processes, while providing a coating that can help the even coverage of zinc.
5. Mechanical stir-dipping: Mechanical stirring-dipping is to immerse and stir the processed objects in zinc concentrate solution through high-frequency electromagnetic stirrer, in order to obtain uniform and even zinc coating on the objects. During the stirring process, a metallurgical reaction between processed objects and zinc concentrate solution can be obtained.
6. Drying: Drying is to dry the plated objects with low-temperature hot air, so as to remove the surface moisture of the processed objects.
7. Post-galvanizing treatment: Post-galvanizing treatment is to continue to plate zinc above the objects that have been galvanized, in order to increase the thickness of zinc layer, as well as improve the erosion-resistance and wear-resistance of processed objects.
The mechanical galvanizing process has the following four characteristics compared with the traditional electroplating process:
1. Low cost: The cost of mechanical galvanizing is much lower than that of traditional electroplating.
2. Environmental protection: The environmental pollution caused by mechanical galvanizing is much less than that of traditional electroplating.
3. High efficiency: The plating speed of mechanical galvanizing is much faster than that of traditional electroplating.
4. Good adhesion: The zinc layer plated with mechanical galvanizing has good adhesion, which can be comparable to that of traditional electroplating.
