Surface treatment detection

A. Roy, there is a test for chromate on galvanized surfaces that uses an acidic solution of diphenylcarbizide. If chromate is present a reddish purple color appears when this material has been on the surface for several minutes. There is also a method that measures chrome on the surface using a xray fluorscence method but this require the purchase the instrument.

If a phosphate coating has been applied, you should be able to mark on the surface by dragging you fingernail across the surface. The mark appears as a white line. Phosphate coating can also be measured using a weigh strip weigh method using ammonium dichromate as the stripping solution. If oil has been applied, a weigh strip weigh method can be used to determine how much oil has been applied per unit of surface area stripped. In this stripping procedure, a solvent is used to remove the oil. These tests are probably not as simple as you would like, but they will provide the data you are looking for.