Characterization of zinc phosphate coatings obtained from modified baths

Zinc phosphate coatings obtained from phosphating baths modified with long-chain flotation surfactants, were characterised by scanning electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy techniques. The results of these characterisation studies were correlated to the mechanism proposed to explain the influence of these additives on the nature and quality of the phosphate coatings obtained in their presence, as well as to explain the behaviour of these coatings in aggressive environments. These studies indicate that the surfactant additives not only control the initial nucleation process but also participate during the subsequent stages of coating deposition, and regulate its growth.