Zinc-rich primer

A preparatory coating applied to a substrate before an adhesive, sealant, coating or waterproofing membrane, improving adhesion by sealing porosity, binding dust or providing a chemically compatible surface. Primer selection depends on both the substrate and the product to be applied over it.

The process of coating steel or iron with zinc by immersion in a bath of molten zinc, forming metallurgically bonded zinc-iron alloy layers with an outer zinc surface. The coating protects both as a barrier and sacrificially, continuing to protect the steel at small areas of damage.

A block of a more electrochemically active metal, commonly a zinc, aluminium or magnesium alloy, electrically connected to a structure so that it corrodes preferentially and protects the structure. Anodes are consumed in service and are inspected and replaced as part of planned maintenance.

A standardised description of the visual cleanliness of a steel surface before painting, defined in ISO 8501-1 as Sa grades for blast cleaned steel and St grades for hand and power tool cleaned steel. Coating specifications state the required preparation grade because coating life depends heavily on surface preparation.

A naturally occurring lamellar form of iron oxide used as a flake pigment in intermediate and finish coats of heavy duty protective paints. The overlapping flakes align parallel to the surface, lengthening the path for moisture penetration and shielding the binder from ultraviolet light.