Epoxy powder coatings hot mixed with nanoparticles to improve their abrasive wear

Abstract

The wear resistance of organic coatings is a key factor in preserving their barrier effect against corrosion. In this research, epoxy-based powder coatings were loaded with different percentages of SiO2 nanoparticles (1, 2 and 3% by wt.) to improve their wear resistance. The innovative mixing method used to homogenize the nanoparticles in the matrix was a hot mixer. The modified organic powders were applied by electrostatic gun on carbon steel substrates. After curing, sliding wear tests were performed at 5 N using reciprocating wear equipment, and measuring the coefficient of friction (COF). The wear mechanism was analyzed and the width and the depth of each track were measured through scanning electron microscopy (SEM) and optoelectronic microscopy. Wear results were analyzed considering the increase in hardness and scratch resistance, and the decrease in ductility of the coating caused by the nanoparticles. As no wear track was found on 3% SiO2 containing coatings under this load due to its properties, it was decided to perform more tests at higher loads to delve further into its wear mechanisms. This coating withstands wear with very small damage under moderate loads, but starts to show abrasive wear and high COF when the load increases.