Community Research and Development Information Service - CORDIS


This joint research about substitutes to chromates either in conversion treatments or as inhibitors into primers leads to the following conclusions:
-Some of the tested pre-treatments are not only viable alternatives bur may even be superior to chromate pre-treatments.
-The Ti/P organic conversion treatment has given good results on Zi-Ni substrates; the efficiency was equivalent to that of chromates in an aggressive environment with not too high Cl contents.
-Co/Ti treatments may be used as substitutes to mixed oxides.
-A number of Cr-free primers have been tested and seem to be suitable alternatives to primers containing chromates especially on HDG and GalfanTM.
-Our research has again shown that serious discrepancies between accelerated tests and natural exposures may be related to the excessive presence of chlorides.
-Substitution of conventional salt spray test, by others such as cyclic tests, with lower chloride concentrations and UV tests, has to be examined.
-The evaluation has highlighted a number of possible Cr-free alternative systems which may fit for applications such as domestic appliance or interior construction.
-The methods for local measurements at the surface of corroded sheets are emerging techniques which quantify the protecting effect of inhibitors at the cut edges and along scribes.

Further work has to be carried out on:
-Description of these new conversion layers and of their mechanisms of formation.
-Description of the mechanisms of healing.
-Relation between accelerated tests and natural exposures for cut edges.r cut edges.

Additional information

Authors: PORRO A, Labein Bilbao (ES);PUENTE J M, Aceralia, Aviles (ES);MORCILLO M, CENIM, Madrid (ES);GIL SEVILLIANO J, CEIT, San Sebastian (ES);MARANON J, CSI, Lasaca (ES);WILLIAMS B, British Steel plc, Port Talbot, (GB);FERARI V, CSM, Roma (IT);NICOLLE R, IRSID, Maizières-les-Mer (FR)
Bibliographic Reference: EUR 20047 EN (2002), pp.140. Euro: 20.50
Availability: Available from EUR-OP sales agents. URL:
ISBN: ISBN:92-894-2065-0
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