Effect of Lubricants with Different Nature and Properties on Friction in a DLC–UHMWP Endoprosthesis Pair

By using a pendulum tribometer, an effect of lubricants having different nature and properties exerted on friction in an endoprosthesis pair based on a diamond-like carbon coating (DLC) and ultra-high-molecular-weight polyethylene (UHMWPE) has been studied. It is shown that, in contrast to the traditionally used natural formulations based on blood serum or hyaluronic acid, known as ones simulating the friction and properties in the natural synovial fluid, the artificial synovial fluid containing cholesterol liquid crystals inherent in natural synovia, together with compositions based on water-soluble chondroitin sulfates (glycosaminoglycans) containing the products of a cartilage matrix, exhibit much higher values of tribotechnical properties. At the same time, it is noted that the artificial synovial fluid containing cholesterol liquid crystals inherent in natural synovia has shown the best lubrication results, just as previous studies involving a natural cartilage–cartilage friction pair using a pendulum tribometer. This is also in a good agreement with the use of such lubricants for technical applications, in particular, for reducing friction between different solids, especially in metal-based friction assemblies, since they exhibit a high lubrication efficiency in different systems.