The paper works with ultra-high molecular weight polyethylene (UHMW). This polyethylene is widely used in technology, in engineering or its applications are also in the field of medicine in prosthetics in the lining of joint replacements. This wide use is mainly due to its properties. It is mainly its abrasion resistance and very low coefficient of friction (COF), so it has excellent sliding properties. It is these properties that are the subject of research on UHMW polyethylene. The investigation of these properties is always linked in tribological tests to the material in the friction pair, which consists of the material under test (UHMW) and the indenter. For the purpose of tribological testing, 6.35 mm diameter balls of ZrO2 ceramic material and a cobalt-chromium alloy known as Stellit 6 were chosen as indentors. Practical applications are the above mentioned fields of technology, engineering, etc.