Structure and Functional Properties of Colored Glaze Coatings Manufactured by Flame Spraying Onto Thermal Sensitive Substrates

Glazes are attractive materials as they can be applied onto metallic or ceramic substrates to confer on them specific surface properties. They find numerous applications, from art ornamenting to protection against corrosion. Conventional process (vitreous glazing) requires a high temperature treatment (up to 1400 °C, maximum temperature) to fuse the glazes after their effectuation on the surface to be covered. This treatment cannot be applied onto heat-sensitive substrates without severe degradation.

Previous studies showed that manufacturing glaze layers by flame spraying prevents the substrate from thermal degradation. The coating formation mechanisms are different from the ones encountered with crystallized ceramic materials: the high surface tension of glazes prevents the particles from being totally spread (i.e., "dewetting" phenomena). The glaze particles morphology and chemical composition were previously optimized. Furthermore, a design of experiments was realized to adjust operating parameters: impermeable coatings with a smoothed surface could have been manufactured.

 This work aims at manufacturing colored glaze coatings by flame spraying. The colored coatings structures are analyzed and some mechanical properties are determined, in particular Elcomer adhesion and impact tests. Samples ageing behavior is also estimated by freezing-thawing cycles.