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Balance

Sacrificial protection and passivity can be mutually exclusive and passivity can be so well developed that sacrificial activity is suppressed. An AZ coating does not provide the same degree of sacrificial protection as a Z, ZA or ZM coating, which does not have the non-loss passivity of aluminium.

The differences between primarily zinc and primarily aluminium coatings lies in the balance between passivity and sacrificial protection, and for roofing and cladding products in most conditions, an AZ coating provides satisfactory sacrificial protection of cut edges although not as well as a zinc-based coating. The introduction of magnesium into coatings containing aluminium is intended to enhance the cut-edge corrosion resistance of the coatings to provide better all-round performance.

Clause: 
018_009_001_001_000_000_000_000_000
Clause Number: 
18.9.1.1
/cop/trash/corrosion#balance
Draft Clause: 
018_009_001_001_000_000_000_000_000