Showing papers in "Tribology Transactions in 1993"
TL;DR: In this paper, the effects of orientation of surface roughness, entrainment (rolling) velocity, and slide/roll ratio on micro-elastohydrodynamic lubrication (micro-EHL) were investigated under pointcontact conditions using the optical interferometry technique.
Abstract: The effects of orientation of surface roughness, entrainment (rolling) velocity, and slide/roll ratio on micro-elastohydrodynamic lubrication (micro-EHL) are investigated under pointcontact conditions using the optical interferometry technique. Long bumps with constant height and wavelength produced artificially on the surface of a highly polished steel ball are used as a model roughness. It is shown that the asperities are elastically deformed and the magnitude depends on the film factor A, defined by the ratio of the central film thickness based on smooth surfaces to the composite surface roughness, as well as the surface kinematic conditions and the orientation of the asperities. It is also found that a thin or thick oil film formed at the inlet of the contact by a moving rough surface travels through the contact region at a speed very close to the average speed of the contacting surfaces. The possible mechanism is discussed.
114 citations
TL;DR: Fretting wear tests were performed on three titanium alloys, α + β-Ti-6Al-4V, α -Ti-15V-3Al-3Cr-3Sn, and β − Ti-15 V-3 Al-3 Cr-3 Sn, in air as mentioned in this paper.
Abstract: Fretting wear tests were performed on three titanium alloys, α + β-Ti-6Al-4V, α-Ti-15V-3Al-3Cr-3Sn, and β-Ti-15V-3Al-3Cr-3Sn, in air. Friction conditions were chosen in order to get gross slip at the interface. The tangential load was recorded during each cycle of the test. Optical and scanning electron microscopy, grazing incidence X-ray diffraction, energy dispersive X-ray analysis and transmission electron microscopy (TEM) were used to characterize the superficial surface layers of the specimens after the fretting test. Particle detachment was observed in every case and the friction coefficient was always very high. A hard tribologically transformed structure (TTS) was detected in some areas of the superficial layers. TEM revealed that TTS was formed of ultra fine non-oriented grains of alpha-titanium. No beta phase was detected. The wear debris particles were produced from the transformed areas of the contact zone and were then quickly oxidized in the interface. The formation of the TTS is interpreted...
82 citations
TL;DR: In this paper, the crystal structure and properties of fullerenes are described and a mechanism for self-lubricatin is proposed, which can be used for various mechanical and tribological applications.
Abstract: The advent of techniques for producing gram quantities of a new form of stable, pure, solid carbon, designated as fullerene, opens a profusion of possibilities to be explored in many disciplines including tribology. Fullerenes take the form of hollow, geodesic domes, which are formed from a network of pentagons and hexagons with covalently bonded carbon atoms. The C60 molecule has the highest possible symmetry (icosaliedral) and assumes the shape of a soccer ball. At room temperature, fullerene molecules pack in a face centered cubic (fee) lattice bonded with weak van der Waals attractions. Fullerenes can be dissolved in solvents such as toluene and benzene and are easily sublimed. The low surface energy, high chemical stability, spherical shape, weak intermolecular bonding, and high load bearing capacity of C60 molecules offer potential for various mechanical and tribological applications. This paper describes the crystal structure and properties of fullerenes and proposes a mechanism for self-lubricatin...
82 citations
TL;DR: In this article, a new crystalline thin-film material suitable for tribological applications was reported, which was synthesized using DC magnetron sputtering of a highpurity graphite target in an argon/nitrogen plasma using various substrates held at ambient temperatures.
Abstract: This paper reports the discovery of a new crystalline thin-film material suitable for tribological applications. Carbon nitride thin films were synthesized using DC magnetron sputtering of a high-purity graphite target in an argon/nitrogen plasma using various substrates held at ambient temperatures. These thin films consist of mixed amorphous and crystalline phases. Unlike previous work, a significant amount of nitrogen, the NIC ratio exceeding 0.4 in the bulk, was incorporated. Infra-red studies showed that nitrogen was bonded to carbon in the film. These films appeared to be very wear-resistant under lubricated sliding conditions. In dry sliding, carbon nitride gave friction coefficients as low as 0.16, comparable to diamond. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference In San Diego, California, October 19–21, 1992
64 citations
TL;DR: In this article, the development of transfer films atop steel counterfaces in contact with unfilled and bronze-filled PTFE has been studied using X-ray photoelectron spectroscopy.
Abstract: The development of transfer films atop steel counterfaces in contact with unfilled and bronze-filled PTFE has been studied using X-ray photoelectron spectroscopy. The sliding apparatus was contained within the vacuum of the analytical system, so the effects of the native oxide, hydrocarbon, and adsorbed gaseous surface layers of the steel upon the PTFE transfer behavior could be studied in-situ. For both the filled and the unfilled PTFE, cleaner surfaces promoted greater amounts of transfer. Metal fluorides, which formed at the transfer film/counterface interface, were found solely in cases where the native oxide had been removed to expose the metallic surface prior to sliding. These fluorides also were found at clean metal/PTFE interfaces formed in the absence of frictional contact. A fraction of these fluorides resulted from irradiation damage inherent in XPS analysis. PTFE transfer films were found to build up with repeated sliding passes, by a process in which strands of transfer filled in the remaini...
60 citations
TL;DR: In this article, a micro-macrocontact model was used to analyze the contact stresses of EHL bearing and showed that enhanced-finish EHL bearings have longer lifetime than standard finish bearings, and that the predicted subsurface stress maps display the local stress levels for various EHL film thicknesses.
Abstract: The contact stresses of bearings were analyzed by a micro-macrocontact model in which the macrocontact was elastic, and the microcontact was elastic-plastic. Subsurface stress maps were calculated for real contact surfaces, by including roughness, waviness, and profile. The predicted subsurface stress maps display the local stress levels for various elastohydrodynamic lubrication (EHL) film thicknesses and show why enhanced-finish bearings have longer lives than the standard-finish bearings. It is believed that the present approach provides an alternative to the empirical methods that are used for predicting life under thin-film EHL conditions. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in San Diego, California, October 19–21, 1992
56 citations
TL;DR: The film formation behavior of lubricating oils containing zinc dialkyldithiophosphate (ZDDP) additives has been studied in rolling, concentrated contacts using ultra-thin film interferometry.
Abstract: The film formation behavior of lubricating oils containing zinc dialkyldithiophosphate (ZDDP) additives has been studied in rolling, concentrated contacts using ultra-thin film interferometry. It has been shown that ZDDP-containing oils form chemical films which are additional to the elastohydrodynamic (EHD) films produced by the base oil. ZDDP film formation occurs at elevated temperatures and begins in the range of 130°C to 170°C, depending upon the base oil type. The thickness of the films increases with temperature and test time. The ZDDP films formed are typically 5 to 25 nm thick and appear to be solid-like surface coatings. Presented at the 47th Annual Meeting In Philadelphia, Pennsylvania May 4–7, 1992
52 citations
TL;DR: In this article, a new high-pressure, high-shear stress viscometer has been developed with a pressure capability of 300 MPa and shear stress of 26 MPa for shear.
Abstract: A new high-pressure, high-shear stress viscometer has been developed with a pressure capability of 300 MPa and shear stress of 26 MPa for shear which is essentially isothermal in the context of the...
48 citations
TL;DR: The elastohydrodynamic film-forming properties of oil-in-water emulsions in rolling point contacts have been investigated using a combination of ultrathin film interferomelry and short duration TV microscopy.
Abstract: The elastohydrodynamic film-forming properties of oil-in-water emulsions in rolling point contacts have been investigated using a combination of ultrathin film interferomelry and short duration TV microscopy. It has been shown that at slow rolling speeds, all the o/w emulsions tested formed EHD films comparable to those of their water-free components. Above a certain critical rolling speed, which, depended upon the emulsion composition, the film thickness started to decrease. This was due to EHD starvation, and the film thickness/inlet oil meniscus relationships developed for starved oil systems were found to apply to emulsion starvation. At high rolling speeds, the EHD film thickness did not collapse to zero, but instead leveled off at a low value, typically 10 to 30 nm, which persisted to the highest rolling speeds attained. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in San Diego, California, October 19–21, 1992
45 citations
TL;DR: In this paper, a series of sliding tests have been carried out using steel on sapphire contacts, and the temperature of the contact and its environs has been mapped prior to and during scuffing using infrared emission radiometry.
Abstract: An important component of most scuffing models is the concept of a critical temperature at which the lubricant film weakens to such an extent that a significant rise in friction coefficient occurs. This then causes a further rise in contact temperature and positive feedback ensues. However, scuffing models differ as to the location of the critical temperature and the mechanism by which it weakens the lubricant film in the contact. In this paper a series of sliding tests have been carried out using steel on sapphire contacts, and the temperature of the contact and its environs has been mapped prior to and during scuffing using infrared emission radiometry. The results are compared with existing scuffing models, and the role of the contact temperature in scuffing is clarified. Presented at the 46th Annual Meeting In Montreal, Quebec, Canada April 29–May 2, 1991
44 citations
TL;DR: In this article, four-ball wear studies have demonstrated that hydroperoxides formed by oil oxidation can greatly increase wear of rubbing steel parts, while peroxides have no effect on the wear of steel parts.
Abstract: Four-ball wear studies have demonstrated that hydroperoxides formed by oil oxidation can greatly increase wear of rubbing steel parts. Peroxides, in contrast, have no effect on the wear of steel parts. Engine oil components, including the antiwear additive type, the detergent, the dispersant, and the base oil, as well as the type of steel, can all influence the magnitude of the prowear effect of hydroperoxides. Surface analyses by SEM, EDAX, and XRF showed hydroperoxides reduced the surface coating formed by antiwear additives. Wear tests on blends containing potential oil additive reaction products demonstrated that none caused the high wear observed with hydroperoxides. Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991
TL;DR: In this article, the effects of surface roughness, normal load, sliding velocity, and silicone oil content of Acrylonitrile-Butadiene-Styrene (ABS) polymer on static and kinetic friction were studied in a pin-on-di
Abstract: The effects of surface roughness, normal load, sliding velocity, and silicone oil content of Acrylonitrile-Butadiene-Styrene (ABS) polymer on static and kinetic friction were studied in a pin-on-di
TL;DR: In this article, a modified Reynolds equation is obtained from which the bearing behavior can be predicted, and the damper forces are predicted as a function of the eccentricity ratio, and a dimensionless parameter which depends on the yield shear stress.
Abstract: The flow properties of electrorheological (ER) fluids change with the application of an electric field. These materials have been proposed as smart lubricants. Existing ER fluids are best described by the Bingham model. The Bingham material is described by two parameters, yield shear stress and viscosity. When the shear stress magnitude exceeds the yield shear stress, quasi-Newtonian flow results; otherwise, the material is rigid. For many ER fluids, the yield shear stress is proportional to the square of the applied electric field. In the present study, the Bingham model is applied to the one-dimensional squeeze film damper. A rigid core forms midway across the film, the core thickness being proportional to the yield shear stress. A modified Reynolds equation is obtained, from which the bearing behavior can be predicted. The damper forces are predicted as a function of the eccentricity ratio, and a dimensionless parameter which depends on the yield shear stress. Calculations are performed for a simple ro...
TL;DR: In this paper, the molecular composition of adsorbed ZnDTPs on aluminum oxide (Al2O3) surfaces has been studied by inelastic electron tunneling spectroscopy (IETS), a highly sensitive molecular spectrograph specifically applicable to surface species at low coverages.
Abstract: Zinc dithiophosphates (ZnDTPs) have been used extensively as antiwear agents for over 30 years. The mechanism of action of these remarkable materials is not well understood. In particular, the molecular composition of the antiwear film produced by the ZnDTPs remains an area requiring investigation. In this paper, the molecular composition of adsorbed ZnDTPs on aluminum oxide (Al2O3) surfaces has been studied by inelastic electron tunneling spectroscopy (IETS), a highly sensitive molecular spectroscopy specifically applicable to surface species at low coverages. As such, it complements other surface science techniques for determining surface compositions. A vibrational spectroscopy, IETS utilizes the literature on group characteristic frequencies available from the very extensive correlations developed for infrared and Raman spectra. Thus, functional groups may be identified that are formed by the reaction of a lubricating oil additive with a metal surface covered by a native oxide. By IETS, we show that Z...
TL;DR: A numerical analysis of the lubricating film in spiral groove upstream pumping mechanical seals, accounting for the occurrence of cavitation, has been performed in this paper, where the axial stiffness and leakage rate have been determined as functions of the operating conditions and design parameters.
Abstract: A numerical analysis of the lubricating film in spiral groove upstream pumping mechanical seals, accounting for the occurrence of cavitation, has been performed. Axial stiffness and leakage rate have been determined as functions of the operating conditions and design parameters. Results indicate that properly designed spiral groove upstream pumping seals will perform well in a double seal arrangement, with good stiffness characteristics and negative leakage of the buffer fluid. However, results also suggest that such seals will operate poorly as single seals, due to negative stiffness resulting from excessive cavitation. Presented at the 47th Annual Meeting In Philadelphia, Pennsylvania May 4–7, 1992
TL;DR: In this paper, the tribo characteristics of self-lubricating 40mm-bore ball bearings with a retainer of glass cloth-polytetrafluoroelhylene (PTFE) laminate, which has elliptical pockets with a large pocket clearance, were tested under thrust loads at speeds up to 50000 rpm, 2 million DN, in liquid hydrogen (LH2) and in liquid nitrogen (LN2).
Abstract: The tribo characteristics of self-lubricating 40-mm-bore ball bearings with a retainer of glass cloth-polytetrafluoroelhylene (PTFE) laminate, which has elliptical pockets with a large pocket clearance, were tested under thrust loads at speeds up to 50000 rpm, 2 million DN, in liquid hydrogen (LH2) and in liquid nitrogen (LN2). During testing, the bearing torque, outer-race temperature, and electric resistance between the inner and outer races were monitored to verify the formation and rupture of a PTFE transfer film. Testing showed that the bearings having the elliptical retainer pockets were superior to the conventional bearings with circular pockets. It was determined that at the maximum inner race spinning velocity of about 5 mls a PTFE transfer film could sustain the maximum Hertz stress, up to about 2000 N/mm2, in LH2, without severe film rupture resulting in bearing seizure. In LN2, the critical load capacity of PTFE transfer film with bearing seizure was about 2700 N/mm2. Presented as a Society of...
TL;DR: In this paper, the authors proposed a reciprocal asymptotic isoviscous pressure α* as a replacement for the initial pressure viscosity coefficient α0 based on the Weibull pressure transformation.
Abstract: The classical elastohydrodynamic film thickness solution which assumes a purely exponential variation of viscosity with pressure requires a pressure-viscosity coefficient. In general, liquid lubricant viscosity varies with pressure such that the local pressure-viscosity coefficient is a function of pressure, making the determination of the pertinent parameter for film thickness difficult. Blok proposed a reciprocal asymptotic isoviscous pressure α* as a replacement for the initial pressure viscosity coefficient α0 based on the Weibull pressure transformation. The pressure-viscosity characteristics of seven liquid lubricants were measured with a falling body viscometer to pressure of 0.76 GPa and α0 and α* were calculated. Viscosity and glass transition results were applied to a model in current usage. The EHD film thickness was measured using interferometry supported by the measurement of the refractive index at elevated pressure. The reciprocal asymptotic isoviscous pressure was found to be more correct ...
TL;DR: The flexure-pivot bearing as mentioned in this paper is a one-piece bearing that offers rotodynamic stability approaching that of a tilting-pad bearing without the complexities of a multi-piece design.
Abstract: Many of today's modern turbomachines, especially those running at high speeds and high power ratings, require the superior stability characteristics of tilting-pad journal bearings to prevent rotor-dynamic instabilities. Until now, the design complexity of tilting-pad bearings has precluded their use in many small, high-volume applications where cost and size are important. This paper introduces a new one-piece journal bearing design, the flexure-pivot bearing, that offers many of the beneficial rotodynamic advantages of tilting-pad bearings, without the complexities of a multi-piece design. Performance data for a flexure-pivot bearing is shown for an application requiring a highly stable design, illustrating the effectiveness of the flexure-pivot bearing in offering rotordynamic stability approaching that of a tilting-pad bearing. Presented at the 47th Annual Meeting In Philadelphia, Pennsylvania May 4–7, 1992
TL;DR: In this article, a bearing lest rig was developed to characterize the static and dynamic properties of hydrodynamic journal bearings, including operating eccentricity, pressure and thermal boundary conditions, and continuous circumferential pressure and film thickness profiles at multiple axial planes.
Abstract: A bearing lest rig was developed to characterize the static and dynamic properties of hydrodynamic journal bearings. Static measurement capabilities include operating eccentricity, pressure and thermal boundary conditions, and continuous circumferential pressure and film thickness profiles at multiple axial planes. Dynamic stiffness and damping coefficient measurements are achieved using steady state harmonic excitations generated by a two-axis shaker system. All essential data for a complete understanding of one particular bearing can be collected simultaneously. To ensure high quality results, the rig was designed to minimize the influence of measurement uncertainties on the derived dynamic coefficients. Complete details are described. The rig is configured to lest bearings with 70 mm bore diameters at speeds up to 2500 rpm and loads up to 6000 N. The data reduction technique is presented along with typical results at one steady operating position for a three-lobe bearing which demonstrate the reproduci...
TL;DR: In this article, the coefficient of friction of paper-based facing for a wet clutch was determined under a variety of sliding conditions, and the transitional friction characteristics of the paper face were investigated.
Abstract: The coefficient of friction of paper-based facing for a wet clutch was determined under a variety of sliding conditions. It is important to investigate the transitional friction characteristics of ...
TL;DR: In this paper, a thermodynamic analysis of a misaligned mechanical face seal is performed and the authors show that the amplitude of temperature variation along the seal circumference due to misalignment is negligible compared to the mean temperature.
Abstract: A thermohydrodynamic analysis is performed for a misaligned mechanical face seal. Temperature variations both across the sealing gap and along its radial and circumferential extent are considered. The energy equation is solved analytically and temperature distribution is presented in an implicit form. It is shown that, in most practical cases, the amplitude of temperature variation along the seal circumference due to misalignment is negligible compared to the mean temperature. The radial temperature distribution can be obtained by solving an equivalent aligned seal whose face separation is reduced by a factor that contains the effect of misalignment. Presented at the 47th Annual Meeting in Philadelphia, Pennsylvania May 4–7, 1992
TL;DR: A numerical method employing a finite volume approach for calculating the rotordynamic force on eccentric, whirling labyrinth seals has been presented in this article, where the SIMPLER algorithm is used to calculate the three-dimensional flowfield within a seal.
Abstract: A numerical method employing a finite volume approach for calculating the rotordynamic force on eccentric, whirling labyrinth seals has been presented The SIMPLER algorithm is used to calculate the three-dimensional flowfield within a seal The modified bipolar coordinate system used accurately describes the geometry of an eccentric seal The turbulent flow form of the fully elliptic Navier-Stokes equations was solved A three-percent eccentric, single labyrinth cavity rotating at 7000 cpm was investigated for three different inlet swirl conditions, each with and without a whirl orbit frequency of 3500 cpm It was found that the circumferential pressure variation around the downstream tooth periphery is by far the most important contribution to both rotordynamic force components Thus the flowfield details near each tooth throttling should be carefully considered Further, a substantial increase of shaft whirl frequency was found to decrease and increase the effect of cavity inlet swirl on Ft and Fr , re
TL;DR: In this paper, the authors present the evolution of a seat recession simulator, which has been used to study the effects of component misalignment on the wear process of valve seat wear.
Abstract: The minimization of valve seat wear is a critical pursuit of engine manufacturers. In order to achieve this goal, a means to objectively rank various valve materials and designs must be used. This study traces the evolution of a seat recession simulator. The simulator has been used to study the effects of component misalignment upon the wear process. Lateral and angular misalignment have both been found to play a key role in the wear process. Utilizing microscopy techniques to compare the wear of engine run valves to that of the rig run valves demonstrated a strong correlation between the wear patterns. The seat wear test rig is thought to be a valid simulation of the engine valve seat recession process. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference In San Diego, California, October 19–21, 1992
TL;DR: In this article, the performance of a variety of space lubricants was compared under boundary and elastohydrodynamic lubrication (EHL) conditions, and the types of fluids studied were naphthenic mineral oil, paraffinic mineral oils, polyalphaolefin, and silahydrocarbon.
Abstract: Performance of a variety of space lubricants was compared under boundary and elastohydrodynamic lubrication (EHL). The types of fluids studied were naphthenic mineral oil, paraffinic mineral oil, polyalphaolefin, and silahydrocarbon. The silahydrocarbon and the polyalphaolefin lubricants exhibited lower traction under similar conditions. A specific additive package increased the traction of the polyalphaolefin. Volatility characteristics of some of these fluids were also studied. Presented at the 45th Annual Meeting In Denver, Colorado May 7–10, 1990
TL;DR: In this paper, the shear-rate dependent viscosities of two NLGI grade No. 2 greases, Grease A and Grease B, were measured using a capillary tube viscometer within a temperature range of 5°−35°C.
Abstract: The shear-rate dependent viscosities of two NLGI grade No. 2 greases, Grease A and Grease B, were measured using a capillary tube viscometer within a temperature range of 5°−35°C. The yield stresses of these greases were directly measured without extrapolation process as a function of temperature. Two types of the yield stresses were found to exist: one was a start-up yield stress below which grease does not start flowing, and the other was a stopping yield stress at which the grease stopped flowing. The former is substantially larger than the latter and should play an important role in the design of an automatic grease pumping system, a system normally operated in an intermittent mode rather than in a continuous mode. In general, the yield stress of Grease A increased with increasing temperatures whereas that of Grease B decreased with increasing temperatures. Continuous pumping tests with Grease A were conducted in four different diameter pipes. A new friction coefficient-Reynolds number correlation was...
TL;DR: In this paper, the authors derived the equations for the internal speeds, frictional torque, and heat generation rates for a tapered roller bearing in which one or more rollers are partially or fully jammed.
Abstract: The equations for the internal speeds, frictional torque, and heat generation rates are derived for a tapered roller bearing in which one or more rollers are partially or fully jammed. The simplified differential equations of the motion of the rollers and cage are derived based on an equivalent bearing mechanism concept. Representative data for the steady-state heat generation rates and axle torque are given based on this simplified model. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference In San Diego, California, October 19–21, 1992
TL;DR: In this article, the durability of zirconia-coated rigid disks in various environments reveals a sensitivity to the presence of water vapor during sliding, similar to that of carbon-covered rigid disks.
Abstract: Examination of the durability of zirconia-coated rigid disks in various environments reveals a sensitivity to the presence of water vapor during sliding, similar to that of carbon-coated rigid disks. Among the test environments investigated, i.e. vacuum, dry/moist air, and moist nitrogen, humidity had the greatest effect by increasing the contact life of the disks substantially over that of vacuum or dry air. The dominant factors affecting wear are believed to be oxidation of metallic debris and interaction of the overcoat layer with water vapor. Tests with ferrite read/write sliders on carbon-coated disks suggest that the pin-on-disk test is a valid simulation of the tribological behavior of this system. Carbon film thickness measurements indicate that the carbon film remains intact without appreciable thinning until the point of failure.
TL;DR: In this paper, the authors presented measured and calculated characteristics of a tilting pad journal bearing suitable for high speed machinery, and compared the measured and predicted bearing temperatures and stiffness coefficients over a wide range of values.
Abstract: This paper presents measured and calculated characteristics of a tilting pad journal bearing suitable for high speed machinery. Descriptions are given of the experimental techniques used with this variety of bearing and the theoretical model for predicting performance. Measured values of pad temperature, eccentricity, attitude angle, and the four stiffness coefficients are given for a range of loads and rotational speeds. Data are given for both load on pad and between pad configurations, the two principal loading arrangements. Comparisons are made between the measured and predicted bearing temperatures and stiffness coefficients over a wide range of values. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in San Diego, California, October 19–21, 1992
TL;DR: In this article, the tribological characteristics of transfer films from polytetrafluoroethylene (PTFE)-based, glass-fiber reinforced composites to 440C stainless steel disks were evaluated in an ultra-high vacuum, using a dual-pin-on-disk friction tester.
Abstract: Tribological characteristics of transfer films from polytetrafluoroethylene (PTFE)-based, glass-fiber reinforced composites to 440C stainless steel disks were evaluated in an ultra-high vacuum, using a dual-pin-on-disk friction tester. The transfer film was formed by rubbing a composite pin against a 440C stainless steel disk. A friction test was then carried out using the other 440C stainless steel pin. Three types of composites with the additives, Mo, Ag or MoS2 were tested. Outstanding tribological performance was obtained with the composite containing molybdenum. X-ray photoelectron spectroscopy (XPS) analysis of the transfer film showed both PTFE and metal fluoride to exist on the disks for all the composites tested. Therefore, metal fluoride is not the reason for the outstanding performance observed using the composite with the molybdenum additive. Electron probe micro analysis (EPMA) studies showed that, for the case of the composite containing molybdenum, considerable transferred fluorine was foun...
TL;DR: In this paper, a laser holographic photoelastic experimental verification is proposed to analyze the oil film pressure distribution and load characteristics, considering the pressure-viscosity effect of the lubricant and the pressureelasticity effect of surface.
Abstract: The lubrication condition between the slipper and the oblique plate of a high pressure pump affects its operating life. One of the studies in this paper is to analyze the oil film pressure distribution and load characteristics, considering the pressure-viscosity effect of the lubricant and the pressure-elasticity effect of the lubricating surface. In addition, a laser holographic photoelastic experimental verification is proposed. Another aspect of the study concerns the investigation of the dynamic stiffness properties of the oil film and its experimental verification. The conclusions obtained here provide a new theoretical basis for the design and parameter selection of a J high pressure plunger pump.