Oxide barrier coatings on steel strip by spray pyrolysis

ZnO, TiO2 and ZrO2 thin films have been deposited by chemical spray pyrolysis onto differently galvanized steel strips (ThyssenKrupp Steel) for its potential use as protective layer against degradation due to ambient impact during long-term outdoor exposure. The steel strips shall be used as base material for unglazed solar collectors (EU project: SOLABS)11http://www.solabs.net/. ust thus comply including all its overcoats (oxide barrier layer, selective layer, antireflection layer) with manufacturing requirements for collectors as moulding, forming, cutting, etc. In order to improve the so-called weatherability of the galvanized steel strip by coating it with an oxide barrier layer, conditions as total substrate coverage, high compactness and high optical transparency of the oxide barrier layer have to be fulfilled. In this communication, we present a comparative study of the morphological, structural, chemical and optical properties of potential oxide barrier layers (ZnO, TiO2, ZrO2) deposited by spray pyrolysis onto three types of galvanized steel substrates. Results from complementary analytic techniques as scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–VIS–IR spectroscopy demonstrate that highly compact thin oxide layers can be produced protecting the steel substrate.