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The purpose of this paper is to present the results of research into using an additive to SAE 15W/40 engine oil during operation and its influence on lubricating properties (normalised tests) on weld point Pz, non-seizure load Pn, load wear index Ih and on seizure load Pt. The friction pair consisted of a group of four balls and the tested lubricant. Moreover, the author tested the influence of an additive to engine oil (non-normalised tests) on tribological properties, including friction force, wear and the temperature of friction area for the C45 steel/210Cr12 steel friction joint. She also determined the influence of an additive to engine oil on the formation of the operating surface layer. The research results helped to build the model of the boundary layer that was formed as a result of adding an additive to engine oil.

The lubricant properties of engine oil and engine oil to which an additive was added during operation were determined according to PN-76/C-04147. The following are the indexes of lubricant properties: weld point Pz, load wear index Ih, non-seizure load Pn, seizure load and average scar diameter. The Pz, Pn and Ih indexes were determined at abruptly increasing load to the moment of welding of the friction pair. The Pt index was determined at the increasing load of the friction pair from 0 to 800 daN at the speed of 408.8 N/s. The tests of tribological properties (friction force, wear and the temperature of friction area) were conducted for the C45/210 Cr12 friction pair in the presence of a lubricant and a lubricant with an additive.

The modification of SAE 15W/40 engine oil with the additive added during operation resulted in improved indexes of lubricant properties Pz, Pn, Ih and Pt and average scar diameter. The boundary layer for the modified oil breaks after a longer time and at lesser friction force. The modification of the engine oil reduced the wear of the friction pair. After the friction process, element composition in the surface layer of the wear trace and its distribution were determined in relation to applied lubricants. A significant amount of sulphur, phosphorus and oxygen, as well as an insignificant amount of copper, was observed in the wear trace after the friction process in the presence of the lubricant medium. The distribution of elements in the wear trace when the engine oil with the additive was used is steady in the wear trace and outside it. Some sulphur, phosphorus and chlorine were found in the wear trace.

The results of tests on tribological properties (non-normalised tests) confirmed the positive affect of the additive to engine oil on lubricant properties (normalised tests). The modification of the engine oil caused reduced friction force and the reduced wear of the friction pair. The reduction of friction force and wear was the result of the formation of the surface of a greater amplitude density of unevenness tops in the friction process. Moreover, the operating surface layer, created in the friction process when the additive was added to the engine oil, had greater load participation at 50 per cent C. This operational surface layer improved tribological properties, i.e. it reduced value of friction force and wear. The test results were used to build a model of the boundary layer created as a result of the additive added to engine oil.

The effect of different service parameters on the current-carrying tribological properties of CF-Al₂O₃/Cu composites was investigated, and the damage behavior of the composites under different service parameters was probed. The purpose of this study is to provide a theoretical basis for the application of CF-Al₂O₃/Cu composites.

The composites were fabricated by internal oxidation combined with powder metallurgy. The current-carrying tribological properties of CF-Al₂O₃/Cu composites were investigated on an electrical damage test system at different loads and currents.

As the load increases, the wear mechanism of the composite changes from abrasive wear to delamination wear. As the current increases, the oxidation wear and arc erosion of the composites gradually intensified. Under the service parameters of 0–25 A and 30–40 N, the composite has relatively stable current-carrying tribological properties.

This paper could provide a theoretical basis for the practical application of CF-Al₂O₃/Cu composites.

To provide information about technical data; wear behaviour of worn rotor parts in mining industry and for the other application of ferrous alloys.

Wear behaviour of the various filler wires were tested (tensile, hardness, and wear) and compared with each other in the light of microstructure, chemical, and mechanical properties.

The results showed that the wear rates were significantly increased with the increasing load, welding current, wear distance and poor mechanical properties. A larger amount of C, Cr, and Mn specimen showed the best wear resistance since it contained a number of hard MC‐type carbides and coarse grains. Furthermore, for all materials the weight loss increases linearly with the increasing of welding arc current, load and wear distance.

It would be interesting to search about the toughness values and fatigue behaviour of these materials. It could be the good idea for future work could be concentrated fracture surface analysis of these materials.

For these materials choosing the right chemical composition of the filler material, certain arc current and ideal microstructure is crutial for the wear response.

The main value of this paper is to contribute and fulfil the mechanical properties of welding wires that is being studied so far in the literature such as the effects of chemical composition, applied road range, and arc current on the tensile, hardness and wear behaviours of the welding wires.

The mechanical and tribological properties of polymers and polymer composites vary with different environmental conditions. This paper aims to review the influence of humidity/water conditions on various polymers and polymer composites' mechanical properties and tribological behaviors.

The influence of humidity and water absorption on mechanical and tribological properties of various polymers, fillers and composites has been discussed in this paper. Tensile strength, modulus, yield strength, impact strength, COF and wear rates of polymer composites are compared for different environmental conditions. The interaction between the water molecules and hydrophobic polymers is also represented.

Pure polymer matrices show somewhat mixed behavior in humid environments. Absorbed moisture generally plasticizes the epoxies and polyamides and lowers the tensile strength, yield strength and modulus. Wear rates of PVC generally decrease in humid environments, while for polyamides, it increases. Fillers like graphite and boron-based compounds exhibit low COF, while MoS2 particulate fillers exhibit higher COF at high humidity and water conditions. The mechanical properties of fiber-reinforced polymer composites tend to decrease as the rate of humidity increases while the wear rates of fiber-reinforced polymer composites show somewhat mixed behavior. Particulate fillers like metals and advanced ceramics reinforced polymer composites exhibit low COF and wear rates as the rate of humidity increases.

The mechanical and tribological properties of polymers and polymer composites vary with the humidity value present in the environment. In dry conditions, wear loss is determined by the hardness of the contacting surfaces, which may not effectively work for high humid environments. The tribological performance of composite constituents, i.e. matrix and fillers in humid environments, defines the overall performance of polymer composite in said environments.

Paper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads.

AlSi12 alloys are used to manufacture the compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition.

AlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg₂Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content.

In this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.

Aluminium alloys are frequently applied in automotive and other industries, since they provide mass reduction. Besides positive effects, aluminium alloys have their shortcomings reflected, first of all, in inappropriate tribological properties of these materials. The aim of this research was to enable the production of cheap aluminium alloy matrix composite with favourable combination of structural, mechanical and tribological properties, focusing on the tribological behaviour.

The A356 Al-Si alloy was used as a matrix for producing metal matrix composites in compocasting process. Three different materials, in form of particles, were added to the matrix (Al₂O₃, SiC and graphite). Hardness and tribological properties (wear, friction and wear mechanism) of heat-treated (T6) samples were examined and compared. Tribological tests were carried out on ball-on-block tribometer under dry sliding conditions. Sliding was linear (reciprocating). Counter body was alumina ball. Average velocity was 0.038 m/s (max. 0.06 m/s), sliding distance was 500 m and normal load was 1 N.

The effect of two different ceramic particles and graphite particles on tribological properties of obtained composites was evaluated. Wear resistance of composites reinforced with SiC particles was higher and coefficient of friction was lower compared to the composite reinforced with Al₂O₃ particles. A dual hybrid composite (with SiC and graphite particles) showed the lowest value of wear rate and friction coefficient. Dominant wear mechanism for all tested material was adhesion.

It seems useful to continue the work on developing hybrid composites containing soft graphite particles with A356 Al-Si alloy as matrix. The major task should be to improve particles distribution (especially with higher graphite content) and to explore tribological behaviour in diverse working conditions.

Particulate composites with A356 aluminium alloy as a matrix produced in compocasting process using ceramic particles (Al₂O₃, SiC) were investigated in many researches, but there are only few detailed analyses of dual composites (with the addition of ceramic and graphite particles). In some previous studies, it was shown that compocasting process, as relatively cheap technology, can obtain good structural and mechanical characteristics of composites. In this study, it was shown that even a low graphite content, under specified conditions, can improve tribological properties.

This study aims to evaluate the dry-sliding tribological properties of fine-grained tin–bronze alloy under reciprocating sliding conditions.

A fine-grained tin–bronze alloy was processed by multiaxial forging (MAF) and annealing treatment. Friction and wear experiments were conducted on a reciprocating sliding tribometer. Microstructure, tensile mechanical properties, hardness, wear rate, friction coefficient and wear morphologies of coarse-grained sample, MAF sample and MAF and annealing sample were compared.

After MAF, the strength and hardness increased distinctly, but the elongation decreased. The wear rate is increased, though friction coefficient is lower. Weaker work hardening leads up to higher sliding wear rate. After MAF and annealing, the alloy has higher strength, hardness and elongation. Lower wear rate of the alloy is correlated with the higher hardness, elongation and work hardening. The adhesion wear and abrasive wear are the primary wear mechanism.

It was found that the fine-grained alloy shows lower sliding wear rate only by combining severe plastic deformation with heat treatment. The process of MAF and annealing is useful in improving the wear resistance of tin–bronze alloy.

The purpose of this paper is to investigate the mechanical and wear properties of Y-TZP/Al₂O₃ nanocomposites.

In this paper, the Y-TZP/Al₂O₃ nanocomposites with different crystal-sizes are designed and fabricated by hot pressing. Their mechanical and anti-wear properties are investigated, and the wear mechanism is studied by scanning electron microscopy, X-ray diffraction, and transmission electron microscope and so on.

The experimental results indicate that the wear of Y-TZP/Al₂O₃ nanocomposites can be divided into two regimes: mild wear regime and normal wear regime. In mild wear regimes, the relationship between wear resistance (ɛ) and hardness (H) of the material can be described as: ɛ−1∝H−1. The corresponding relationship among wear resistance, hardness and toughness (K_IC) of the material in normal wear regime can be described as: ɛ−1∝H−1K _IC −4.

In this paper, the mechanical and anti-wear properties of Y-TZP/Al₂O₃ nanocomposites are systematically investigated. The relation between mechanical properties and wear resistance is revealed.

The purpose of this paper is to investigate the tribological properties of a textured lubricating wear-resistant coating modified by nano-SiC at a high temperature. Its aim is to explore the influence of a new composite method on the organisation and structure of sprayed coatings as well as the evolution rules governing their high-temperature tribological properties.

A KF301/WS2 lubricating, wear-resisting, coating was prepared on matrix material GCr15 by applying supersonic plasma spraying technology. On the basis of this sample, using nano-SiC particles as a filler, the KF301/WS2 nano-modified coating with its round, pit-type texture was prepared by laser re-melting technology and a surface texturing technique. Two kinds of coating micro-organisations and structures were examined by scanning electron microscopy, and the tribological properties of both the modified and conventional coatings were studied at a high temperature.

Results showed that nano-particles could effectively improve the coating micro-structure, and make the structure denser and more uniform, thus significantly increasing the wear resistance of the coating. When the friction and wear processes were stable, the friction coefficient decreased by 13 per cent, while the wear loss decreased by 45.9 per cent.

This research concentrating on the study of the process and performance of coatings doped with nano-particles by laser re-melting incorporating simultaneous surface texturing, and studies of their high-temperature tribological properties. That is because applying nano-particle modification technology to the development of wear-resistant coatings, and by applying the nano-particles to such coatings by thermal spraying technology, they can achieve a modification of the coating which makes the structure denser and more uniform.

This study aims to compare the friction and wear behaviors of Fe_68.3C_6.9Si_2.5 B_6.7P_8.8Cr_2.2Al_2.1Mo_2.5 bulk metallic glass (BMG) under sliding using dry, deionized water-lubricated and oil-lubricated conditions. The comparison was performed using a unidirectional ball-on-flat tribometer under different applied loads, and the results were compared to the properties of a conventional material, SUJ2. Fe-based BMG materials have recently been attracting a great deal of attention for prospective engineering applications.

As a part of the development of Fe-based BMGs that can be cost-effectively produced in large quantities, an Fe-based BMG Fe_68.8C_7.0Si_3.5B_5.0P_9.6 Cr_2.1Mo_2.0Al_2.0 with high glass forming ability was fabricated. In the present study, the friction and wear properties of Fe-based BMG has been comparatively evaluated under dry sliding, deionized water- and oil-lubricated conditions using a unidirectional ball-on-flat tribometer under different applied loads, and the results were compared to the properties of conventional material SUJ2.

The results show that the Fe-based BMG had better friction performance than the conventional material. Both the friction coefficient and wear mass loss increased with increasing load. The sliding wear mechanism of the BMG changed with the sliding conditions. Under dry sliding conditions, the wear scar of the Fe-based BMG was characterized by abrasive wear, plastic deformation, micro-cracks and peeling-off wear. Under water- and oil-lubricated conditions, the wear scar was mainly characterized by abrasive wear and micro-cutting.

In this investigation, the authors developed a new BMG alloy Fe_68.8C_7.0Si_3.5B_5.0P_9.6Cr_2.1Mo_2.0Al_2.0 to improve the friction and wear performance under dry sliding, deionized water- and oil- lubricated conditions.