Layered double hydroxides (LDHs) as functional materials for the corrosion protection of aluminum alloys: A review

The search for new alternatives to replace chromate-based coatings is a matter of great importance. Since their official ban due to the raised concerns of hexavalent chromium to the human health and the environment, significant efforts have been devoted to finding a more suitable alternative for the corrosion protection of aluminum alloys. However, the task has been quite challenging since the potential replacement needs to fulfill several requirements both in terms of cost and exceptional corrosion performance. Layered double hydroxides (LDHs) have generated a lot of interest in the past few years. They have been proposed as prospective candidates to replace chromate based protective systems. The particular structure of LDH nanocontainers allows them to intercalate a number of corrosion inhibitors and release them on demand under the action of corrosion relevant triggers. Moreover, their flexible use as pigments in paints or as a pre-treatment directly as conversion layers makes their implementation even more convenient. This review presents a critical view to the studies performed till today on LDHs for corrosion protection of aluminum alloys.