Maximum corrosion resistance will be obtained using a microcrystalline calcium zinc phosphate, with very little difference between this and the macrocrystalline zinc phosphate. These two systems offer the widest range of powder coating and subsequent process variable selections. Iron phosphates require a chrome-containing rinse in order to provide the desired corrosion resistance, and also limit the choice of available coatings. Corrosion resistance performance of various coatings on cold-rolled steel is compared in chart form.