As the name suggests, free iron testing is used to identify free iron. This test is mainly done on nickel and stainless steel. The presence of free iron on the surface of stainless steel or nickel makes the metal more prone to corrosion, and therefore decreases the life expectancy of the material. Free iron testing will help to assure the quality of materials used, and help set a more accurate life expectance for your materials. Two main tests are used in detecting the presence of free iron: the ferroxyl test and the copper sulfate test.

When ferroxyl (potassium ferricyanide) is in the presence of free iron on the surface of a metal, it reacts and changes to a blue color. This test is extremely versatile and detects even the smallest amount of surface free iron. Our field technicians have the experience necessary to perform this test in an effective and precise manner.

Copper sulfate acts as a less sensitive alternative to the ferroxyl test. If free iron is present on the surface, copper will deposit on the surface as well, and a bronzish sheen will remain even after the solution is rinsed off. While this test is just as effective as ferroxyl, it cannot be used on low chromium stainless steels, or certain other alloys.