EPOXY ANTIFRICTION COATINGS FILLED WITH THE RICE HUSKS ASH TREATED WITH SURFACTANTS

Abstract

The use of epoxy antifriction coatings can significantly reduce thermal stress in the friction zone and expand the coating working temperature interval while keeping high wear resistance. The paper considers the effect of non-activated and activated by surfactants silicate filler – rice husk ash on the physicochemical and mechanical properties of epoxy materials applied as antifriction coatings. All studied samples of rice husk ash, both initial and activated with surfactants, have an alkaline surface nature. The study identified that all cationic quaternary ammonium salts (QAS) reduce the pH of rice husk ash. At the same time, nonionic OXIPAV increases this indicator. Activation of the rice husk ash surface, both by the quaternary ammonium salts and aminosilanes, significantly reduces the porosity of this silicate. In this case, the average pore diameter does not change significantly, and their specific surface area decreases significantly, to a lesser extent, when activated by nonionic quaternary ammonium salts. The application of quaternary ammonium salts and aminosilanes in the amount of 33 % for activation of the surface of the investigated silicate filler reduces its modifying effect in epoxy compositions, regardless of the chemical structure of the surfactants used, which is not a typical effect. Therefore, the authors assumed that the suboptimal concentration of quaternary ammonium salts and aminosilanes was used. The study identified that the optimal concentration of 50 % alcohol solution of KATAPAV is 14.7–21 %. In this range of the QAS content, there is a significant increase in hardness (about 40 %), a slight decrease in wear (about 10 %), and a significant decrease in the coefficient of static friction (up to 2 times). At the same time, the authors observed an increase in adhesion to metal up to 3 times and bending strength up to 25 %. Thus, rice husk ash activated with an optimal amount of quaternary ammonium salts is an effective modifier of epoxy coatings, which improves their antifriction properties and increases wear resistance, hardness, strength, and adhesion characteristics.