## 1 Introduction  
Modern engineering faces many challenges related to energy efficiency and material consumption in mechanical processes. Approximately 23% of the world's total energy consumption is related to tribological processes. Of this, 20% is for overcoming frictional resistance, while 3% is for the energy required to produce a new part [1, 2, 3]. Through the use of new materials and advanced lubrication technologies, it is possible to reduce energy losses due to friction and wear by 18% in the short term (8 years) and by 40% in the long term (15 years) [2]. One promising solution for reducing the costs associated with tribological processes is the use of modern carbon materials, such as carbon nanotubes, fullerenes, graphene, nanodiamonds, and expanded graphite. The use of these materials can significantly reduce friction and wear in polymers [4; 5; 6], metals [7; 8; 9; 10], and ceramic materials [11; 12; 13]. Of these materials, expanded graphite is particularly noteworthy, as it exhibits favorable tribological properties due to its layered crystalline structure [14; 15; 16; 17; 18; 19]. This structure provides strong bonds within the layers, weak bonds between the layers, and good susceptibility to delamination. Due to these properties, expanded graphite is widely used in engineering applications as a component of lubricants and composite materials. In engineering components such as bearings, brakes, seals, and brush motors, it significantly improves performance and extends service life. The researchers analyzed the potential to improve the tribological properties of selected engineering components, such as brakes and bearings, by adding expanded graphite. [PERSON] et al. [20] conducted a comparative study of brake pads made from composites containing carbon materials in the form of expanded graphite, natural graphite flakes, and synthetic graphite flakes. It was shown that pads with the addition of expanded graphite had the highest thermal stability. Furthermore, the use of expanded graphite in the composite contributed to a decrease in wear and an increase in fade resistance. [PERSON] et al. [17] introduced expanded graphite into resin-based friction materials, resulting in a 22.4% decrease in the wear rate compared to natural graphite. The stability of the friction coefficient was also improved, especially at high operating temperatures. According to [PERSON] et al. [21], the addition of 2% expanded graphite to friction materials increased the coefficient of friction by 24.1% at 350 \({}^{\circ}\)C and enhanced resistance to fading by 19%. However, for a graphite content of 4%, the wear rate decreased by 37.3%. It was also indicated that during braking, the presence of expanded graphite in brake pads reduces the development of cracks and delamination of the material. Expanded graphite is also used in sliding materials, which, unlike friction materials, have low coefficients of friction. [PERSON] et al. [18] investigated the effect of adding expanded graphite to a polyetherimide (PEI) composite. The addition of graphite was shown to reduce the friction coefficient and wear index by 35% and 87.2%, respectively, compared to the composite without the additive. [PERSON] et al. [22] indicated that temperature played a key role in reducing the friction coefficient and wear index values of the composites tested with the expanded graphite additive. It was found that operating at elevated temperatures (200-250 \({}^{\circ}\)C) promotes the formation of a homogeneous graphite sliding layer between the mating surfaces. This layer provides a reduction in the coefficient of friction and wear of the mating surfaces. It has also been reported that at high temperatures, surface wear increases with the rising load. [PERSON] et al. [23] investigated that the tribological properties of polyimide-based (PI) composites containing nanoscale expanded graphite (nano-EG) are highly dependent on the nano-EG content under dry sliding conditions. Compared to pure PI, the wear resistance of PI/nano-EG composites has increased 200-fold.