The Ratio Related to: Phosphate Corrosion Resistance

Summary

The role of the hopeite and phosphophyllite phosphate coating ratios in determining the corrosion resistance of mild steel when coated with cathodic electroprimer and paint are reviewed and discussed. Attention is drawn to the problems associated with adequately defining the ratio, its calculation and broader relevance. Other factors contributing to corrosion resistance are highlighted in terms of method of phosphate application, bath working temperature and chemistry, chromium after rinsing and workpiece vibration, etc. Arguments are forwarded to support the contention that the P/P + H ratio is not sufficient in itself to enable accurate prediction of corrosion performance in all circumstances.

Additional information

Notes on contributors

M. O. W. Richardson

Dr. Mel Richardson is a senior lecturer in Materials Engineering in the Institute of Polymer Technology and Materials Engineering at Loughborough University of Technology. He leads a research group concerned with composite materials based on polymer matrices and polymeric coatings providing toughness especially for the building industry. He is author of over 70 papers and is editor of the book ‘Polymer Engineering Composites ‘.

D. R. Gabe

Dr. David Gabe is a graduate of the University of Wales (Cardiff) going on to do a Ph.D. at the University of Sheffield.

Initially he was employed by the Steel Company of Wales Ltd. and British Steel Corporation before becoming a lecturer in metallurgy at the University of Sheffield. Since 1974 he has been Senior Lecturer and Reader in Materials Engineering at Loughborough University of Technology and in 1989 became Director of the Institute of Polymer Technology and Materials Engineering, at L. U. T. He heads a research group in Corrosion Protection and Coating Technology.