Galvanizing refers to the surface treatment technology of plating a layer of zinc on the surface of metal, alloy or other materials for aesthetic, rust prevention, etc. The main method is hot galvanizing.
Zinc is soluble in acid and alkali, so it is called amphoteric metal. Zinc hardly changes in dry air. In humid air, a dense basic zinc carbonate film will be formed on the zinc surface. In the atmosphere containing sulfur dioxide, hydrogen sulfide and marine atmosphere, the corrosion resistance of zinc is poor, especially in the atmosphere containing organic acid at high temperature and humidity, the zinc coating is vulnerable to corrosion.
The standard electrode potential of zinc is -0.76V. For the steel substrate, the zinc coating belongs to the anodic coating, which is mainly used to prevent the corrosion of steel. Its protective performance has a great relationship with the coating thickness. The protective and decorative properties of zinc coating can be significantly improved after passivation, dyeing or coating with light protecting agent.
