Tuning Adhesion at Metal/Oxide Interfaces by Surface Hydroxylation

Abstract

–The control of adhesion at metal/oxide interfaces is of key importance in modern applications, whenever three-dimensional metal clusters or two-dimensional metal overlayers are to be synthesized on an oxide support. By focusing on the zinc/alumina system, we address here one of the long-standing issues in this context, which is the poor wetting of wide band gap oxides by noble and post-transition metals. It has recently been recognized to have detrimental industrial consequences for the adhesion of anticorrosive zinc coatings to new high strength steel grades. We have combined photoemission, thermal desorption, and plasmonics with atomistic simulation to describe the energetics of zinc deposits on dry and hydroxylated α-Al2O3(0001) surfaces. Both experimental and computational results show that an activated reaction of the metal with the OH-covered surface, followed by hydrogen desorption, produces dispersed interfacial moieties involving both oxidized Zn species and under-coordinated oxygen ions that le...