Corrosion protection with nanoscale anticorrosive pigments in coatings

For the efficient corrosion protection of metals and alloys with primers as well as self-healing effects, properties of anticorrosive pigments such as particle size, interaction with binder, barrier effect, release of active species and their transport to the metal surface are of a great importance. Conventional and nanoscale corrosion protective phosphate derivates have been investigated to clarify their influence on all these factors and ultimately on the efficiency of the corrosion protection of metallic substrates. The chosen pigments were incorporated into a solvent based epoxy primer and tested on steel, galvanized steel and aluminium substrates with short time tests, electrochemical methods and atmospheric weathering. SEM images of paint cross sections were also taken to visualize the pigment particle distributions. Such advantages of nanoscale pigments as an efficient corrosion protection, good self-healing and barrier properties have been noticed. An influence of the metal surface roughness on these properties was also observed.