The influence of the nature of carboxylate precursors on the composition and tribological performance of copper-containing nanomaterials

Abstract

In this study, a comparative study of nanomaterials formed during thermolysis at 300 °C of two representative metal carboxylates (copper capronate and valerate) was carried out. The obtained nanoparticles (NPs) were studied using X-ray diffraction, atomic force microscopy and sedimentation analysis. Copper(I) oxide and copper are the main decomposition products of copper capronate. The crystallite size of copper(I) oxide is from 20 to 30 nm, and that of Cu crystallites is from 11.2 to 11.3 nm and is practically independent of the thermolysis time. The decomposition of copper valerate produces copper(I) oxide with a size of 20 to 50 nm, and the dispersion of particles depends on the thermolysis time of the samples. Analysis of copper-containing nanomaterials as additives to lubricants (Ciatim-221 and liquid paraffin) was carried out in terms of their tribological behavior using a pin-on-disc and four-ball machine tribometers. The introduction of copper(I) oxide NPs reduces the friction coefficient of Ciatim-221 lubricant and liquid paraffin by 26% and 39%, respectively. The microstructure of the friction surface depends on the presence of copper oxide NPs in the lubricant and on the nature of the lubricant base.