Against the Corrosion of Stainless Steel

Against the Corrosion of Stainless Steel

Stainless steel or non-rusting steel is usually employed because of its high resistance to corrosion. Apart from alloys and structures, this is primarily determined by the surface structure.

Passivation with POLINOX-Protect TC by POLIGRAT increases the corrosion resistance of stainless steel surfaces to a degree that far exceeds what has hitherto been achieved using traditional techniques.

POLINOX-Protect TC can be used on austenitic, ferritic and martensitic (hardened) stainless steels as well as on all surface finishes.

POLINOX-Protect TC is a two-phase thermochemical process with a completely new principle of operation, making use of an effect which was hitherto not known. In the first phase the components to be passivated are subjected to chemical treatment in an immersion bath for two to four hours. This is followed in the second phase by a targeted thermic treatment in air. The application time lasts for at least ten minutes, whereby the temperature varies according to material and lies between 100°C and 200°C, in order to achieve the best results.

Surfaces treated with POLINOX-Protect TC demonstrate, apart from the improved corrosion resistance, a considerably higher resistance to discolouration resulting from raised temperatures.

When compared with untreated, milled surfaces in original condition, a variety of stainless steel qualities demonstrated after treatment with POLINOX-Protect TC a noticeable increase in the pitting potential (measured in artificial seawater). In the case of the ferritic steel 1.4016 the improvement amounted to approx. 550 mV, and for the austenitic materials 1.4301 and 1.4571 it was approx. 900 mV and 600 mV respectively. In the salt spray test the surfaces treated with POLINOX-Protect TCdemonstrated a service life which in some cases was increased by a factor of ten compared with passivation using nitric acid.

For additional information please contact:
POLIGRAT GmbH Valentin-Linhof-Strasse 19 D-81829 Munich
Tel. +49 (0) 89 42778-0 Fax +49 (0) 89 42778-309 E-mail