镀锌钢板的表面白锈和红锈的分析及预防措施

天物彩板专注彩板行业17年——更多镀锌钢板的表面白锈和红锈的原因_天津镀锌楼承板厂家请拨打网站上方电话咨询

白锈和红锈是无花镀锌钢板的常见缺陷。不同厚度的镀锌层会对白锈和红锈的产生时间造成危害吗？
证明材料的镀锌层厚度对镀锌钢板表面白锈产生时间没有影响；镀锌层厚度对红锈的形成时间有影响。镀锌层越厚，红锈的潜伏期越长。
那么镀锌钢板表面的白锈和红锈是如何产生的呢？

White rust and red rust are the common defects of no flower galvanized steel sheet. The different thickness of galvanized layer will do harm to the generation time of white rust and red rust?

Let's prove that the thickness of the galvanized layer of the material has no harm to the white rust generation time on the surface of the galvanized steel sheet; The thickness of zinc coating has an effect on the formation time of red rust. The thicker the zinc coating is, the longer the incubation period of red rust is.
So how does the white rust and red rust on the surface of the galvanized steel sheet produce?
Zinc is an extremely active metal material. The surface of zinc will change with the water vapor in the air to form multilayer porous and sticky Zn (OH) 2. Then, Zn (OH) 2 will further react with carbon dioxide in the atmosphere to form a thin, high-density, adhesive basic zinc carbonate (2znco3.3zn (OH) 2), which can also prevent further corrosion of the zinc layer.
When the galvanized steel sheet is closely stacked and placed in the humid air, there is no free flowing air on the surface between the galvanized steel sheets, and the local surface of the galvanized layer will not produce the chemical change of forming the above-mentioned corrosion product protective film, but will produce electrochemical corrosion and white rust. The mechanism of white rust is actually the principle of "oxygen concentration corrosion battery".
The key to the severity of white rust lies in the composition of condensation water between coatings and the duration in the environment. If the condensed water contains chlorides from seawater, the conductivity of water will be increased, which will increase the rate of electrochemical corrosion and accelerate the corrosion rate of zinc coating.