Visual appearance and scratch resistance of high performance thermoset and thermoplastic powder coatings M. Barletta 1,* , A. Gisario 2 , F. Trovalusci 1 , S. Vesco 1 1 DipartiŵeŶto di IŶgegŶeria MeĐĐaŶiĐa, UŶiǀersità degli Studi di ‘oŵa Tor Vergata, Via del Politecnico, 1 – 00133 Roma (I) 2 DipartiŵeŶto di MeĐĐaŶiĐa ed Aerospaziale, La SapieŶza UŶiǀersità degli Studi di ‘oŵa, Via EudossiaŶa, 18 – 00184 Roma (I) * Corresponding Author e-mail: barletta@ing.uniroma2.it Abstract . A Đoŵparatiǀe eǀaluatioŶ of eleĐtrostatiĐ spraLJ aŶd hot dippiŶg fluidized ďed to deposit tǁo differeŶt organic paints belonging to the class of thermoplastic (PPA571, an alloy of acid modified polyolefins) and thermoset (TGIC-free transparent pigmented bronze polyester) powders was performed. Visual appearance of the investigated coatings was evaluated by color, gloss and coating thickness measurements as well as by the determination of the surface morphologies. Micro-mechanical performance of the coatings was assessed by progressive load scratch tests. Hot dippiŶg fluidized ďed is found a fast deposition technique as, after substrate pre-heating, it takes just few seconds to have the part completely powder coated. On the other hand, electrostatic spray deposition is a potentially selective coating technique, but it lasts longer (generally, 6 to 15 s) and, moreover, the coated parts must be post-cured for long time (at least, 15 min) and at high temperature (150-200°C) to give rise to the formation of continuous films. Indeed, whilst hot dippiŶg fluidized ďed is found particularly suitable for the deposition of thick and smooth thermoplastic coatings, electrostatic spray deposition is found the most viable technique to deposit thinner and highly scratch and wear resistant thermoset coatings. Key words: Electrostatic spray; Fluidized bed; Powder coating; Visual Appearance; Scratch.