The coating is formed via immersion in a dilute phosphoric acid solution and is dark grey in appearance.
The standard measurement method for phosphate coatings is by coating weight, as determined by customer specification. By itself, the phosphate coating offers minimal corrosion protection—the heavier the coating weight the higher the degree of protection, but this protection is significantly enhanced by the application of an oil. Phosphate may also serve as a base for Teflon, Xylan, or paint.
Phosphate is also known by the trade name Parco Lubrite, is sometimes called Parkerizing.