Characterisation of amorphous phosphate coatings onto carbon steel surfaces

This study continues the authors' investigation of the newly developed product KAF-09OF and concerns the preparation and characterisation of amorphous phosphate coatings on carbon steels. KAF-09OF is a liquid concentrate of ammonium and alkaline phosphates, stabilising additives - buffers, softeners, activators (both inorganic and organic), as well as surfactants - a non-ionic and an anionic detergents. Gravimetric and polarisation methods, X-ray fluorescence analysis, transmission electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy have been used to determine the effect of pH (2-6), temperature conditions (20-80 degrees C) and agitation rate (0-2000 rev min(-1)) on the process of phosphating using this developed product. Coating thicknesses, compositions, structures and passivation characteristics in the phosphating baths with different concentrations of KAF-09OF have been analysed.