Large area zirconia coatings on galvanized steel sheet

Amorphous zirconia coatings have been produced by chemical spray pyrolysis on large areas of aluminized steel sheet, using the roll-to-roll technique (coil coating). SEM analysis has shown that the zirconia film is very dense without pores, covering homogeneously the steel surface of 0.4 m width (coil width). XPS and FTIR investigations revealed that no residuals from the precursor solution, in particular, water or carbon, are retained in the film. The protective character of the zirconia coating for the steel substrate has been investigated with electrochemical methods. Electrochemical corrosion experiments have shown that the corrosion resistance has been increased in saline as well as in acid conditions by more than one order of magnitude.