Synthesis of micro-structured zinc particles by thermal evaporation and their application in zinc containing coatings for steel corrosion protection

Abstract

Micro-structured zinc particles with a variety of morphologies are synthesized by thermal evaporation technique. The zinc particles, which exhibit spherical (oblate), irregular-shaped polygonal and leave-like morphologies, are used to fabricate epoxy-based zinc-rich coatings for steel corrosion protection in heavy-duty environments. The assessment of their performance as sacrificial pigments highlights the significant influence of zinc particle morphology and size on coating properties. Accelerated salt spray test indicates that compared to commercial zinc dust, the synthesized irregular-shaped polygonal and leave-like zinc particles exhibit superior anticorrosion performance. EIS and OCP measurements indicate that enhanced barrier properties are obtained with the spherical (oblate) zinc particles due to their dense packing, while prolonged cathodic protection is achieved with the irregular-shaped polygonal and leave-like zinc particles due to the presence of highly electrochemically active zinc particles and the enhanced formation of protective simonkellite crystals on the coating surface.