Lewis Acid-Base Properties of a Low Carbon Aluminium Killed Steel Substrate

Abstract

An important factor in achieving maximum adhesion of a particular coating system to the substrate lies in the proper preparation of the substrate prior to the application of paint. The Lewis acid-base properties of the outer metal surface play a determinant role in many of these applications, and the chemical reactions involved  therein. In this work, the wetting properties of a low carbon aluminium killed (LCAK) substrate have been largely modified by a chemically activated surface treatment. XPS analysis was performed on the   surface.Wettability in water, a polar and protic probe liquid, and in α-bromonaphthalene, a non-polar and aprotic probe liquid, of theLCAKsurface is strongly modifiedwhentheLCAKsurface is treated with dilute formic  acid and warm water. Formic acid forms formate ions which have a higher reactivity with respect to molecular species and are able to react with the exposed surfaces, changing the relative structure of the hydroxyl layer.

KEYWORDS: XPS, Lewis acid-base, wettability, steel, surface.