A laser-based technique for the coating of mild steel with a vitreous enamel

Marked changes in the wettability characteristics of EN8 mild steel were ob served after high-power diode laser (HPDL) surface treatment of the metal. The morphological, microstructural and wetting characteristics of the steel were determined using optical microscopy, scanning electron microscopy (SE M), X-ray photoemission spectroscopy (XPS) and wetting experiments by the s essile drop technique. Improvements in the wetting action of the mild steel after HPDL surface treatment were identified as being the result of: HPDL- induced melting of the mild steel surface, which brought about a reduction of the surface roughness; and a small increase in the polar component of th e surface energy and an increase in the surface O-2 content of the mild ste el resulting from HPDL treatment. This work has demonstrated that the use o f HPDL radiation to alter the wetting characteristics of mild steel in orde r to facilitate improved enamelling is a real possibility. (C) 2001 Elsevie r Science B.V. All rights reserved.