Sol-Gel Coatings on Non-Oxide Planar Substrates and Fibers:A Protection Barrier Against Oxidation and Corrosion

摘要

Sol-gel coatings on non-oxide subatrates can be use to prevent high temperature degradation and to improve wet corrosion resistance.Alumina coatings were investigated.The starting precursor was aluminium sec-butoxide,Modified withchelation ligands such as 2,4-pentranedione or acrylic acid to prevent its precipiation in the presence of water.Stainless steel plates and Hi-Nicalon SiC fibers are often utilid in different kinds of application and thus were selected as substrates.Thin films were deposited from the modified alkoxide solutions using dip-coating techniques.The parameters governing the process such as the aging of the sols,the viscosity,the withdrawal rate and the thermal treatment were invesitgated.The films were characterized (morphology,thickness) and showed an interesting behaviour as protection barrier in an aggressive medium.