Solid particle erosion of a coating composed of clay in a polystyrene matrix

In this work, erosion tests were carried out to study the wear resistance of a coating made of montmorillonite-MMT clay in a crystal polystyrene-PS matrix. The MMT clay was modified and purified with bromide quaternary salts (hexadecyltrimethyl ammonium chloride). The coating preparation was by liquid via dissolving 25% crystal polystyrene in a solution of 70% ethyl acetate and 30% acetone, after this, modified montmorillonite was added and the coating application was by immersion of the substrate (AISI 6061 aluminium) in the liquid phase polymer coating. The substrates were coated with five layers of coating and the percentage of montmorillonite varied between 0.7-1.5 wt%. An erosion rig similar to that shown in ASTM G76-95 was used to perform the tests. The glass bead particles had a particle size between 200-240 µm. Tests were carried out using impact angles, 30°, 45°, 60° and 90° with a velocity of 2.5±0.5 m/s. The abrasive flow rate was 5.0±0.5 g/s. The room temperature was between 35 °C and 40 °C. Chemical compositions of the particles, substrate and the coating were obtained using energy dispersive X-ray analysis (EDS). In addition, SEM images were used to identify the wear mechanisms. Finally, AFM was used to obtain the 3D roughness profiles of the coating surface before tests.