Test medium and method for detecting phosphorus segregates in metallic material

Abstract From the Canadian patent

An aqueous solution containing 0.00005 to 0.2 mol/1 of copper ion and 0.0001 to 1.0 mol/1 of nitrate ion is effective to detect phosphorus segregates in a metallic material, particularly cast steel. Segregated phosphorus can be detected by etching a surface of steel to be tested attaching test paper onto the steel surface applying the, aqueous solution to the paper maintaining the paper in, contact with the steel surface for a sufficient time and, removing the paper from the steel surface. A red print is obtained when the solution is pH 6 or higher. A blue print is obtained by following the above steps and further, treating the paper with a color reagent containing molybdate ion, and then …