(1) W.R.Alstar
a) Conditions at the cut. When the product is cut, the cross section shows coat-drooped part and exposed-substrate part.
b) Conditions in an early period. Red rust (Fe oxide) develops on exposed-substrate part if it gets wet with rain or some other water in early stages of installation.
c) Conditions after certain years. Corrosive growth of Al, S and O develops over red rust some years after installation and such growth works to suppress corrosion of the coating layer and substrate.

Fig.-4. Sketches depicting changes noted on the cut end of W.R.Alstar over certain lengths of time