24. How does the zinc coating corrode in the soil?

In certain soils, zinc coatings form a protective zinc carbonate layer that provides anodic protection for steel pipe substrates. However, the effectiveness of this protection varies depending on soil properties. According to research data, when soil pH ranges between 4.3 and 9.2, eight samples underwent 3-6 year tests. Six of these trials demonstrated minimal corrosion of the zinc coating. Notably, the zinc layer experienced the most severe corrosion in alkaline soils with high electrical resistivity and elevated moisture content.
Generally speaking, the average corrosion rate of zinc coating on galvanized steel pipe is 1.56-280 g/m2·y.