For many years, it has been state of the art to use zinc dust in heavy duty corrosion protection according to SSPC Paint 20. The recent revision to SSPC Paint 29 allows the use of zinc in a flake-shaped form in heavy duty corrosion protective systems provided the performance meets the specification requirements.

Since zinc flakes have a significantly higher surface area compared to zinc dust, formulations using zinc flakes need to be different from previously used zinc rich primers based on dust to achieve adequate performance.

The presentation outlines fundamental formulation principles using zinc flakes in corrosion protective primers and explains where new options for formulating can lead to improved paint characteristics (storage stability, sprayability and the like) while meeting Paint 29 requirements.

In addition comparative Open Circuit Potential OCP data is presented and a final look onto commercial aspects is made.