镀锌钢板产生白锈的原因及如何避免

存放镀锌彩钢板时，应特别注意防止镀锌层出现白锈。白锈不仅损坏外观，还会使镀锌层减少，导致产品质量恶化。因此，白锈是一个警告信号，表明储存环境差，应立即处理。

1白锈形成的原因
镀锌彩钢板表面与空气接触后会氧化，形成一层很薄的氧化膜，可用作保护膜防止进一步氧化。但是，如果在空气湿度高的条件下长期存放，空气中的二氧化碳（CO2）会与锌结合，形成白色粉末白锈。
一般来说，白锈被露水或雨水浸泡后迅速产生。尤其是当湿气暴露在外时。
2什么是冷凝
冷凝是指由于温度的变化，过饱和的水蒸气凝结成液态水。日常生活中常见的例子：如果把装有冰水的容器从冰箱中取出，容器外就会有水滴。另外，当白天气温高，晚上变冷时，树木和花朵上会出现露水。同样，钢板表面也会产生结露。
三。如何防止白锈：
（1） 表面处理是在镀锌钢板生产中进行的。
a、 铬酸处理
将 镀锌彩钢板浸入铬酸溶液中，在锌层表面形成低活性膜。即使这种铬酸盐膜稍有擦伤，伤口附近的铬酸盐也会溶解在水中，聚集到伤口部位，重新形成新的膜。这种自我保护能有效地防止生锈。
铬酸处理主要是为了不上漆，而且涂有铬酸的表面微黄，不应与生锈混淆。
b、 加油：
在 镀锌彩钢板上涂油以防止空气和锌直接接触的方法。对于冷凝和水浸，具有很强的防锈效果。但是，钢板表面的油污必须在油漆前由用户擦去。
c、 磷酸盐处理
如果要使用镀锌钢涂漆，则可采用磷酸盐涂层。磷酸盐能牢固地附着在镀锌表面，表面疏松多孔，能为镀层提供良好的立足点，获得很强的附着效果。在用户方面，只要简单脱脂，就可以使用油漆。

Special attention should be paid to prevent white rust on zinc coating when storing galvanized steel sheet. White rust not only damages the appearance, but also reduces the zinc coating, resulting in the deterioration of product quality. Therefore, white rust is a warning signal indicating that the storage environment is poor and should be treated immediately.

1. Causes of white rust formation
The surface of galvanized steel sheet will be oxidized in contact with air, and form a very thin oxide film, which can be used as a protective film to prevent further oxidation. However, if it is stored for a long time under the condition of high humidity in the air, the carbon dioxide (C02) in the air will combine with zinc to form white powder white rust.
Generally speaking, white rust is produced rapidly after being soaked by dew or rain. In particular, it occurs when the moisture is exposed.
2. What is condensation
Condensation refers to the condensation of supersaturated water vapor into liquid water due to the change of temperature. Common examples in daily life: if the container containing ice water is taken out from the refrigerator, there are water droplets outside the container. In addition, when the temperature is high during the day and it becomes cold at night, dew will appear on trees and flowers. In the same way, dew will be produced on the surface of steel plate.
3. How to prevent white rust:
(1) The surface treatment is carried out in the production of galvanized steel sheet.
a. Chromic acid treatment
Dip galvanized steel sheet into chromic acid solution to form low activity film on the surface of zinc layer. Even if this kind of chromate film is slightly bruised, the chromate near the wound will dissolve in water and gather to the wound site to form a new membrane again. This kind of self-protection can effectively prevent rust.
Chromic acid treatment is mainly used for the purpose of not painting; moreover, the surface coated with chromic acid is slightly yellow and should not be confused with rust.
b. Oiling:
The method of coating oil on galvanized steel sheet to prevent direct contact between air and zinc. For condensation and water immersion, it has a strong anti rust effect. However, the oil on the steel plate surface must be wiped off by the user before painting.
c. Phosphate treatment
If galvanized steel is to be used for painting, phosphate coating may be applied. Phosphate will adhere firmly to the galvanized surface, and the surface will be loose and porous, which can provide a good foothold for the coating and obtain strong adhesion effect. On the user's side, paint can be applied as long as simple degreasing is applied.