“…The combination of these requirements makes the tribosystem extremely challenging for the material pairing in terms of thermo-mechanic, sliding and wear properties. Conventional dry running piston machines use PTFE (Polytetra uorethylene) piston rings bene tting from their self-lubricating properties when sliding against metallic -usually mild steel or cast iron -surfaces [14]. However, as pressure differentials of over 100 bar will be necessary for use in hydrogen technology, materials with much higher strength are required.…”
The energy revolution is of highest priority to achieve the climate targets defined in the 2015 Paris Agreement. With the power-to-gas concept, electric energy is stored as hydrogen gas. State-of-the-art reciprocating compressor technology can realize high pressures with high volumetric flow rates for gas supply. The main challenges in designing machines suited for these operating conditions are the high mechanical stresses acting on piston sealing rings. The high shear forces and the need of minimal gap sizes demand material pairings with high wear resistance and excellent sliding properties. Present research investigates the life cycle limiting wear mechanisms present in the piston compressor, to develop advanced concepts for piston rings and cylinder tribocontacts. In detail PI (polyimide) and PPS (polyphenylene sulphide) materials were reinforced with CF (carbon fibre) and PTFE (Polytetrafluoroethylene) to fulfil the demands of this highly stressed tribosystem. The wear mechanisms were analysed utilizing SEM (Scanning Electron Microscopy) on cross sections cut into the depth of the counter surface material with FIB (Focused Ion Beam), to investigate the abrasion and material deposition. 2D STEM (Scanning Transmission Electron Microscopy) mapping supported by EDX (Energy Dispersive X-ray Spectroscopy) were performed to visualize the depth profile of chemical elements on the wear track after tribotesting.
“…The combination of these requirements makes the tribosystem extremely challenging for the material pairing in terms of thermo-mechanic, sliding and wear properties. Conventional dry running piston machines use PTFE (Polytetra uorethylene) piston rings bene tting from their self-lubricating properties when sliding against metallic -usually mild steel or cast iron -surfaces [14]. However, as pressure differentials of over 100 bar will be necessary for use in hydrogen technology, materials with much higher strength are required.…”
The energy revolution is of highest priority to achieve the climate targets defined in the 2015 Paris Agreement. With the power-to-gas concept, electric energy is stored as hydrogen gas. State-of-the-art reciprocating compressor technology can realize high pressures with high volumetric flow rates for gas supply. The main challenges in designing machines suited for these operating conditions are the high mechanical stresses acting on piston sealing rings. The high shear forces and the need of minimal gap sizes demand material pairings with high wear resistance and excellent sliding properties. Present research investigates the life cycle limiting wear mechanisms present in the piston compressor, to develop advanced concepts for piston rings and cylinder tribocontacts. In detail PI (polyimide) and PPS (polyphenylene sulphide) materials were reinforced with CF (carbon fibre) and PTFE (Polytetrafluoroethylene) to fulfil the demands of this highly stressed tribosystem. The wear mechanisms were analysed utilizing SEM (Scanning Electron Microscopy) on cross sections cut into the depth of the counter surface material with FIB (Focused Ion Beam), to investigate the abrasion and material deposition. 2D STEM (Scanning Transmission Electron Microscopy) mapping supported by EDX (Energy Dispersive X-ray Spectroscopy) were performed to visualize the depth profile of chemical elements on the wear track after tribotesting.
“…It is one of the reason why PA composites exhibited better anti-wear performance, as previous researchers have also observed. 33 Figure 22.Surface roughness values of PTFE, PA, PP composites.…”
Section: Resultsmentioning
confidence: 99%
“…It is one of the reason why PA composites exhibited better antiwear performance, as previous researchers have also observed. 33…”
Section: Influence On Surface Topographymentioning
confidence: 99%
“…32 Researchers have explored tribological and wear mechanisms using experimental and numerical wear simulation methods. [33][34][35][36][37][38] Johansson et al, 33 for example, divided the sliding process into two stages (runningin and steady-state) and found that a smooth interface allowed for low wear rates in both. Amine et.al 34 examined wear rate and coefficient of friction of PTFE-based composites filled with 30% bronze microparticles as a function of load, sliding speed and lubrication.…”
To explore the potential wear performance of commonly utilized hydraulic system polymer components, we investigated the effects of different working conditions on the frictional and wear behaviors of three polymer sealing materials in this study. Polytetrafluoroethylene (PTFE), nylon (PA), and polypropylene (PP) composites were prepared using copper (Cu) and glass fiber (GF) as fillers. The tribological and wear properties (wear rate, surface appearance, wear patterns) of the sealing composites were evaluated. The results showed consistent trends toward increasing average coefficient of friction as load and speed increased for PTFE. The incorporation of filler improved the wear resistance of the composites. The addition of Cu particles showed lower coefficient under higher load and sliding speed. PA with continuous glass fiber (CGF) sealing composites showed lower coefficient, less wear volume, and relatively smoother wear zone surfaces than PTFE-based composites or PP with short glass fiber (SGF). We propose that PA-CGF outperforms other materials in regards to fatigue and friction and wear even under extremely high silding speed,as well as sealing properties.
“…It has been experimentally confirmed that taking into account the surface topography is a significant factor influencing the running-in process. A similar approach was used by the authors of the works [5,6], where the significant factors are the surface roughness parameters [5], contact pressure [6].…”
The paper presents the results of mathematical modeling of tribosystems running-in processes when various factors are changed: design parameters of tribosystems, which are taken into account by the form factor; tribological properties of the lubricating medium; rheological properties of composite materials in the tribosystem; roughness of friction surfaces; load and sliding speed. By comparing the theoretically obtained results, by modeling according to the developed models, with experimental data, it was established that the mathematical model adequately reflects the running-in processes taking into account the changes in constructive, technological and operational factors. Applying the Cochrane criterion, it was established that the obtained experimental results are homogeneous and reproducible. The maximum value of the coefficient of variation of the values of the volumetric wear rate and the coefficient of friction is within the limits v = 12,3 - 26,5%. The value of the simulation error is within the limits v = 7,7 - 12,9%.
A rating of factors that maximally affect the processes of running-in of tribosystems in the conditions of extreme lubrication has been obtained. In the first place is the roughness of the friction surfaces, the coefficient of variation v = 26,5%. In the second place – the load on the tribosystem during running-in, the coefficient of variation v = 20,8%. In third place is the value of sliding speed during running-in, the coefficient of variation v = 18,6%. The conclusion made must be taken into account when developing a rational program for running-in tribosystems in conditions of extreme lubrication.
The methodical approach of applying the acoustic emission method in the study of tribosystem running-in processes is presented. It is proved in the work that in order to determine the volume rate of wear during tribosystem running-in, it is necessary to register and analyze the fourth cluster from the general acoustic emission signal. The sources of signal generation of the fourth cluster are microcutting and plastic deformation of protrusions of the roughness of the friction surface, which is characteristic of the first stages of running-in.
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