Passivation a sudden process operated by nature
The Passivation treatment, reached the end of the whole galvanizing process, reduces the time needed for zinc to react naturally to atmospheric agents. Its main purpose is to prevent that under certain climatic conditions the just galvanized, and therefore still active, external part of the materials starts reacting with moisture from the atmosphere to form zinc hydroxide. This becomes evident when it manifests itself by forming a pale film that can be unattractive in architectural applications. However, the so-called “white rust” does not affect the quality of the already formed protective coating in any way.
A passivation process consists in dipping the toughened artifacts into an aqueous bath containing organic resins. The passivating layer that is deposited in the surface protects the zinc and steel alloy until its spontaneous passivation. Thanks to the achievement of passivation, the galvanizing process can be considered as concluded.
Under normal environmental circumstances, galvanizing activates passivation spontaneously, changing the product’s appearance from a light gray to bright opaque shades with a characteristic outer spangle.