New routes for improving adhesion at the metal/α-Al2O3(0001) interface

Rémi Cavallotti (1, 2) , Ha-Linh Thi Le (2) , Jacek Goniakowski (3, 2) , Rémi Lazzari (3, 2) , Jacques Jupille (2) , Alexey Koltsov (1) , Didier Loison (1)

1 ArcelorMittal Maizières Research SA
2 INSP - Institut des Nanosciences de Paris
3 INSP-E9 - Oxydes en basses dimensions

With the advent of new steel grades, the galvanic protection by zinc coating faces a new paradigm. Indeed, enrichment in strengthening elements prone to oxidation such as Al, Mn, and Si, leads to the formation of oxide films that are poorly wet by zinc. We study herein routes for improvement of adhesion at the model Zn/α-Al 2 O 3 interface by metallic additions. As a first step, with help of ab initio results on adsorption characteristics of transition metal adatoms at α-alumina surfaces, we establish and rationalize clear trends in the behavior of both metal-alumina interaction strength and in the relative thermodynamic stability of configurations with weakly and strongly bound metal adatoms. The reasons of enhanced binding strength of transition metals, such as Cr, maintained regardless the precise alumina termination and surface charge state are pointed out. On these grounds, possible improvements of adhesion in realistic conditions are discussed. It is predicted that an enrichment in transition metals, such as Cr, may produce strongly adhesive interfaces that lead to cohesive cleavage.

Domaines: Matière Condensée [cond-mat]

Rémi Cavallotti, Ha-Linh Thi Le, Jacek Goniakowski, Rémi Lazzari, Jacques Jupille, et al.. New routes for improving adhesion at the metal/α-Al2O3(0001) interface. Physical Chemistry Chemical Physics, 2015, 18 (4), pp.3032-3039. ⟨10.1039/C5CP06435J⟩. ⟨hal-01263694⟩