Process for coating metallic surfaces with coating compositions containing particles of a layered double hydroxide


The invention relates to a process of coating a metallic surface with a composition for coating with a pretreatment composition prior to organic coating, with a passivation composition without intent for subsequent organic coating, with a pretreatment primer composition, with a primer composition, with a paint composition or with an electrocoating composition, wherein each one coating composition or the thereof generated coating contains particles on the base of at least one layered double hydroxide (LDH) phase showing the general formula [1]: [M2+ (1 +- 0.5) - x (M3+,M4+)x(OH)2+- 0.75] An- x / n s mH2O, wherein M2+, M3+ and M4+ are certain divalent, trivalent resp. tetravalent cations, wherein there is no need that cations M3+ are present or there is no need that cations M4+ are present, wherein the anions A and/or neutral or charged molecules A including assemblies with molecules A are selected from the group consisting of anions of hydroxide, fluorides, carbonates, nitrates, sulfates, chromate, chromite, molybdates, phosphomolybdates, phosphates, phosphonates, tungstates, vanadates, azoles, carboxylates, dodecylbenzenes, phenolic compounds, anionic surfactants and biomolecules, and/or wherein each one coating composition or the thereof generated coating contains their at least partially calcined and/or their partially or totally calcined and then rehydrated LDH particles primarily based on a mixture of substances selected from the group consisting of oxides, double oxides, multiple oxides, hydroxides, at least one LDH phase, further anions A and molecules A.

Innovative aspects & main advantages

This patent focus on the development of protective layers (pre-treatments, primers, paints) containing particles based on layered double hydroxides. The role of layered double hydroxides is to store and release in a controlled way active species such as corrosion inhibitors which will contribute for the improvement of the protective performance conferred by the coatings to the metallic substrates. LDHs materials can also work as nanotraps for aggressive anions and improve the barrier effect against the ingress of water and electrolytes from the surrounding environment.


These coatings can be applied in different branches of vehicle industry, from automotive to aeronautical industries.


Ferreira, Mário; Zheludkevich, Mikhail; Tedim, João; Gandubert, Valerie; Schmidt-Hansberg, Thomas; Hack, Theo; Nixon, Sonja; Raps, Dominik; Becker, Diana; Schroeder, Sven

Our Inventors


Universidade de Aveiro
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