Abstract Zeolite coatings prepared by in situ synthesis have been recently proposed as protective treatments for metal surfaces because of their non-toxicity, the high thermal stability and the ability to host useful extra-ions in their framework. In this study, zeolite Y coatings have been grown by direct synthesis on aluminium and stainless steel surfaces. We developed a new method for depositing zeolite Y on aluminium substrates by a single-step synthesis in presence of TEA (triethanolamine). The zeolite coatings have been evaluated by electrochemical tests in neutral (NaCl) and alkaline (Ca(OH) 2) solutions demonstrating a good protective action, especially for aluminium. Although the direct involvement of zeolite coatings in the electrochemical processes was evident, the specific reactions that occur at the zeolite–electrolyte interface have yet to be investigated.