This work reports the preparation of glass-like, environmentally-friendly, cerium-based coatings for active corrosion protection of aluminiumandmagnesiumalloys. It describes the production of ceriumsol–gel sols from ceriumnitrate and their deposition by immersion and automatic spray onto aluminiumandmagnesiumalloys to produce uniform coatings with amorphous (glass-like) structures (CexOy). The coatings have been characterised by profilometry, scanning electron microscopy (SEM), spectral ellipsometry and UV–visible, in order to analyse the structure and density of the glass-like ceriumcoatings aswell as their redox ratio Ce4+/Ce3+ as a function of pH and sintering temperature. Finally, electrochemical measurements (EIS) and standard corrosion tests (neutral salt spray, filiform corrosion, immersion–emersion test and adhesion on embossing and T-bend test) have been performed to study the corrosion behaviour of the cerium glass-like coatings on aluminium and magnesium alloys. EIS measurements confirm the healing or blocking of the defects by the corrosion inhibiting species. Excellent corrosion protection is provided by cerium glass-like coatings, satisfying the most demanding industrial requirements.

The authors acknowledge the funding provided by the European Community, MULTIPROTECT project: “Advanced environmentally friendly multifunctional corrosion protection by nanotechnology”, Contract No NMP3-CT-2005-011783 and especially to EADS Innovation Works, PLALAM.SpA and INASMET-TECNALIA. The EPSRC LATEST2 programme grant is also acknowledged for the financial support of MC.

Peer reviewed