Tribological tests were being carried out employing a ball-on-disc T-eleven tester. The balls had been fabricated from metal, whereas the discs were product of metal, aluminium oxide, zirconium oxide, polyamide and poly(methyl methacrylate). The outline of the system and also the procedures is offered in the literature (Szczerek and Tuszyński https://masone825wci7.wikitron.com/user