BOROSILICATE COATINGS ON MILD-STEEL

Borosilicate glass coatings were obtained on mild steel substrates by the dip-coating sol-gel technique. Different coating solutions were used in fresh and aged conditions. The samples were characterized by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Adhesion to the substrate was evaluated by scotch tape and scratch tests and the effects of coating thickness, solution aging and substrate pretreatment were considered. The capability of borosilicate coatings to improve the oxidation resistance was investigated using the ASTM static oxidation test at 550-degrees-C. Oxidation of the substrate was followed by measuring weight gain with time and following the formation of iron oxides by X-ray diffraction.