Fabrication of zirconium oxide coatings on stainless steel by a combined laser/sol–gel technique

Abstract

A new route of combining sol–gel coating technology and laser processing is developed and used for manufacturing zirconia coatings on stainless steel substrates. In this method, sol–gel zirconia is first synthesised using zirconium (IV) tert-butoxide as precursor and a mixture of isopropanol and water as the solvent. The sol is coated on the substrate by dip-coating, and then the dried sol–gel coating is irradiated by a fibre laser at different energy densities ranging from 4.35 to 10.9 J/mm 2 . Various techniques were applied to characterise the zirconia coatings on the substrate surfaces after laser treatment, including attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy and contact angle measurements. The results show that the fibre laser in continuous wave mode is effective to convert the as-dried amorphous xerogel coating on the substrate into zirconia coatings crystallised in tetragonal structure. The coating surface morphology varies with the laser energy densities and the highest coating uniformity is obtained at the lowest laser energy tested in this research. & 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.