X-ray photoelectron and scanning Auger electron spectroscopy study of electrodeposited ZnCr coatings on steel

Abstract

Zn-Cr alloyed coatings electrochemically deposited are of high interest for leading steel manufacturing companies because of their novel properties and high corrosion resistance compared with conventional Zn coatings on steel. For tuning and optimizing the properties of the electrodeposited Zn-Cr coatings, a broad range of the deposition conditions must be studied. For this reason, two different types of material were investigated in this study, one with a low electrolyte temperature and one with an elevated electrolyte pH, compared with the standard values. Because different corrosion performance and delamination behaviour of the layers were observed for the two types, advanced surface analysis was conducted to understand the origin of this behaviour and to discover differences in the formation of the coatings. The topmost surface, the shallow subsurface region, and the whole bulk down to the coating-steel interface surface were analysed in detail by X-ray photoelectron spectroscopy (XPS) and high-resolution scanning Auger electron spectroscopy to determine the elemental and the chemical composition. For better understanding of the resulting layer structure, multiple reference samples and materials were measured and their Auger and XPS spectra were fitted to the experimental data. The results showed that one coating type is composed of metallic Zn and Cr, with oxide residing only on the surface and interface, whereas the other type contains significant amounts of Zn and Cr oxides throughout the whole coating thickness.

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…A variety of methods are applicable to examining metal coatings. Itani et al 13 studied the properties of two types of zincchromium coatings on steel using XPS and scanning Auger electron spectroscopy. Specic regions of interest were examined: top surface, shallow subsurface and the whole bulk to the steel interface.…”

Effect of PPG-PEG-PPG Co-Polymer on Zn-Cr Alloy Electrodeposition

“…It is worth mentioning that the chemical state of Cr for "as deposited" alloy coatings from an electrolyte having the same base composition [4,16] and coatings subjected to anodic or corrosion treatment has been determined by XPS to be Cr(III) compounds and metallic Cr in depth [11,13].…”

Zn-Cr Alloy Coatings: Electrodeposition and Properties

“…Publications on researches on this subject are limited, fragmentary and incoherent, although literature references to the use of chromium-containing zinc alloys in industry can be found [1,2,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][20][21][22].…”