Despite excellent properties, steel is prone to corrosion that causes a degradation in properties and results in extensive maintenance or replacement of steel, at significant cost. This cost impact has been estimated at US$2.2 trillion or approximately 3% of global GDP2 and attracts significant effort from coating manufacturers in an effort to develop coatings that provide protection against corrosion. Historically, the coatings industry has formulated systems with active inhibitors. Chromium-based coatings have been used extensively, given that they can act both as cathodic or anodic inhibitors. These have however come under pressure on health and environmental grounds forcing the development of a new generation of environmentally friendly systems. Metal phosphates find wide use with zirconia and titanium based fluoro-complexes, demonstrating comparable performance to chromium based pre-treatments.
