Nikolay Ovcharenko

MECHANICAL PROPERTIES OF POLYMER COMPOSITE ANTIFRICTION MATERIALS BASED ON POLYESTERESTERKETONE AND BABBITTS IN TENSILE AND COMPRESSION TESTS AT TEMPERATURES ABOVE 80 °C.

Abstract: The article presents the results of tensile and compressive tests of modern antifriction materials for highly loaded friction units at temperatures ranging from 80 to 180 °C, aimed at evaluating their applicability in sliding bearings operating under elevated temperature conditions. The tests were conducted in accordance with methods regulated by standards. A comparative assessment was performed of the mechanical properties of polymer-based antifriction materials (PCM) based on polyetheretherketone and babbitt alloys ASTM B23 Grade 3 and 7, as well as the TEGOSTAR 738 alloy analogue.
The test results revealed fundamentally different strength mechanisms in PCMs and babbitts, as well as differences in their behavior with increasing temperature. PFMs demonstrate significantly higher values of tensile strength, compressive strength, and yield strength compared to babbitt alloys. Babbitts exhibit pronounced plastic behavior already at 80 °C, with a distinct yield stage; however, their strength sharply decreases above 100 °C, approaching the yield limit, which limits their load-bearing capacity under heated conditions. Although babbitts’ plasticity helps absorb impact loads, it also contributes to frequent failures of babbitt-layered bearings. At temperatures above 120 °C, babbitts undergo significant thermal degradation caused by softening of eutectic structures and microstructural deterioration, while reinforced PCMs maintain stable mechanical properties due to the heat resistance of the polymer matrix and effective load distribution through the reinforcing phase.
The possibility of tuning PCM properties by selecting matrices, fillers, and additives was noted, opening prospects for adapting materials to specific operating conditions. The combination of lower plastic deformability and high strength gives PCMs better shape retention and stability during failure, while their high thermal stability allows their use over a wider temperature range compared to babbitts.
It was confirmed that PCMs outperform babbitts in strength and thermal resistance, enabling an increase in bearing operating temperatures above 200 °C while maintaining performance. This opens prospects for using PCMs in modern rotary systems with high reliability requirements.
The results confirm the superior mechanical characteristics of PCMs and the prospects for their application in highly loaded sliding bearings. Further research is recommended to expand testing, including tribological properties and a wider range of materials. The findings can be used by designers and engineering personnel to broaden the range of bearing materials in the design and modernization of highly loaded friction units of rotary equipment to meet modern demands for load capacity, temperature regime, and reliability.
Keywords: Antifriction materials, tribological units, polymer composite materials, babbitt alloys, thermomechanical testing, tensile tests; compression tests.

Nikolay Ovcharenko

INVESTIGATION OF THE HARDNESS OF POLYMER ANTIFRICTION MATERIALS AND BABBITTS AT ELEVATED OPERATING TEMPERATURES

Abstract: The article presents the results of hardness studies using the Brinell and Shore methods for babbitt alloys ASTM B23 Grade 3 and 7, as well as TEGOSTAR 738, and modern industrial polymeric anti-friction composite materials. The studies were conducted according to standart methodologies at elevated temperatures (from 80 to 180 °C), exceeding the operational temperature range, with the aim of evaluating the influence of temperature on the hardness of the materials. Factors limiting the maximum operating temperature of sliding bearings based on the studied materials were identified. An empirical formula is proposed to establish a correlation between Shore D hardness and Brinell hardness for babbitt alloys and a polymer composite based on polyetheretherketone. The obtained data allow assessing of the hardness of the investigated materials under thermal load and can be used by designers and engineering personnel for the informed selection of bearing materials considering operating conditions, service life, and reliability of friction units.
Keywords: antifriction materials; babbitt alloys; polymer composite materials; sliding bearings; thermomechanical testing; hardness; operating temperature limit; service life; operational reliability

Nikolay Ovcharenko

STUDY OF THE TRIBOLOGICAL PROPERTIES OF ADVANCED POLYMERIC ANTI-FRICTION COMPOSITE MATERIALS FOR HEAVY-DUTY FRICTION UNITS

Abstract: This paper investigates the tribological properties of cutting-edge polymer-based antifriction materials (aPCMs) designed for heavy-duty plain bearings and other friction units of rotating equipment. The study was conducted at temperatures ranging from 80 to 180 °C under loads simulating industrial operating conditions. The research focuses on commercially available industrial-grade aPCMs. The objective of the work is to perform a comparative analysis of the mechanical and tribological properties of various aPCM grades across a wide temperature range, as well as to improve and standardize aPCM testing methodologies for industrial laboratory settings.
The research methodology includes mechanical testing (tensile and compression tests, hardness measurements) and tribological studies to determine friction coefficients and wear rates. Tests were performed in accordance with standards using standard industrial laboratory equipment. Optical microscopy was employed for microstructure analysis.
A comparative assessment of the mechanical and tribological characteristics of various aPCM types was conducted. It was established that at temperatures exceeding 120 °C, all investigated samples maintain stable mechanical properties due to the high thermal stability of the polymer matrix and effective load redistribution by the reinforcing phase. The mechanisms influencing temperature-dependent changes in sliding and static friction coefficients, run-in time, transfer film formation, and counterface abrasion are analyzed in detail. The primary wear mechanisms—abrasive and adhesive friction—are examined, and adequate wear models applicable to the investigated temperature range are proposed, alongside parameters for evaluating aPCM properties and their suitability for tribological applications. The study also considers the specifics of transfer film formation and surface micro-damage processes that determine the stability of the tribosystem.
A comprehensive review of scientific data from other researchers regarding the tribological properties of PEEK/CF composites is provided. The possibility of wide-ranging property adjustment through the selection of matrices, fillers, and additives is highlighted, offering prospects for adapting materials to specific operating conditions. The high mechanical and operational performance of modern domestic aPCMs and their potential for use in various friction units are confirmed.
The results and models obtained can be utilized by designers and engineers in the development and modernization of heavy-duty friction units for power, oil and gas, chemical, and transport equipment to meet modern requirements for load, temperature, and reliability. Additionally, the results can assist material manufacturers in expanding the range of domestic mass-produced aPCMs with adjustable properties. The wide application of aPCMs will significantly reduce operating costs by increasing the service life of friction units, reducing maintenance requirements, and minimizing equipment downtime. The use of domestic components and production technologies reduces dependence on imported analogues and contributes to technological sovereignty.
For further research, it is recommended to expand the range of polymer matrices and fillers, as well as to conduct tests under variable loads and boundary/mixed lubrication conditions. Further advancements in the tribology of polymer composites are expected to lead to a new generation of «smart» anti-friction materials with adaptive properties capable of responding to external operating conditions.
Keywords: tribological testing, friction coefficient, wear, polymer composite materials, anti-friction materials, heavy-duty friction units, plain bearings, mechanical and tribological properties, testing methods, tensile and compression testing, microstructural analysis, wear mechanisms, transfer film, surface micro-damage, peek-based composites.