Ferrinitrate 10% is a solution mainly used in metallography and scientific laboratories. It is an aqueous alcoholic solution of ferric nitrate nonahydrate (CAS No.: 7782-61-8). The solution is particularly suitable for etch polishing copper and copper alloys as well as brasses (colors beta phase), Al bronzes with eutectoid and nickel silver.

The iron(III) nitrate nonahydrate contained in the solution, whose chemical formula is Fe(NO3)3:9H20, reacts with the metal surfaces and initiates the etching process. The addition of ethanol provides improved wetting of the sample surfaces, while the deionized water acts as a solvent. The reaction of the ferrinitrate 10% with the metal surface to be etched produces oxygen and nitrogen-oxygen compounds that exhibit oxidizing effects on the surfaces.

The etching time can range from a few seconds to several minutes, depending on the material. In some cases, post etching with sulfuric acid and sodium or potassium dichromate is required to achieve optimum results. Users of this solution can expect improved surface structure insight and high contrast between the different phases of the alloys. Ultimately, the product enables precise metallographic examination of the treated materials.