Ferroxyl or coppersulfate tests
These tests are chemical surface tests used to detect unintended iron particles on stainless steel. If microscopic iron residues remain on the surface (for example, due to grinding or tools), this can cause severe corrosion later on.
The test works as follows:
A special test solution or test paper is applied to the stainless steel. When the chemicals come into contact with free iron, they react with the iron ions. In the presence of iron, discoloration occurs immediately.
Applications:
Widely used in practice to check whether stainless steel is completely free of iron contamination after a treatment (such as pickling or passivation).
Indispensable in sectors where hygiene and corrosion resistance are crucial, such as the pharmaceutical or food industries.
The test is highly sensitive and can detect even minuscule traces of iron that are invisible to the naked eye.
