INFLUENCE OF SURFACE LASER TEXTURING ON FRICTION AND WEAR OF PTFE DURING SLIDING AGAINST STEEL

Tribologia ◽  
2018 ◽  
Vol 281 (5) ◽  
pp. 27-31
Author(s):  
Piotr KOWALEWSKI ◽  
Tomasz GAŁEK
Keyword(s):  
Microscopic Observation ◽  
Friction And Wear ◽  
Static Friction ◽  
Linear Wear ◽  
Apparent Effect ◽  
Laser Texturing ◽  
Friction Coefficients ◽  
Plate Test ◽  
Surface Laser ◽  
Friction Surfaces

The paper presents research and analysis of PTFE wear during cooperation with steel. The surface of steel elements was subjected to laser texture. Three different patterns of texture were applied to the surface of steel elements. For comparative purposes, an element without a structure was also tested. The experiment was carried out in a roller-plate test on the author’s research stand. As part of the conducted tests, the linear wear of PTFE plates was determined, and the values of the kinetic and static friction coefficients of the tested friction pairs were determined. Steel friction surfaces were also subjected to SEM microscopic observation. The obtained results showed an apparent effect of laser texture on changes in friction and wear of PTFE. This influence is different and depends on the pattern of the texture.

Friction and Wear Behavior of Silicon Carbonitride Processed From the Polymer-Derived Ceramic Route

2005 ◽  
Author(s):  
Tsali Cross ◽  
Somuri Prasad ◽  
Rishi Raj
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Silicon Carbonitride ◽  
Linear Wear ◽  
Polymer Derived Ceramic ◽  
Organometallic Precursors ◽  
Future Work ◽  
Contact Pressures

Polymer derived ceramics (PDC’s) are processed from liquid organometallic precursors by cross-linking the polymers into infusible solids, followed by controlled pyrolysis. No previous work regarding their tribology has been reported. Further, the synthesis of PDC’s as thin films, and the role that the nanostructure plays on the mechanical properties has not been reported. The objective of this research was to evaluate the fundamental tribological behavior of polymer derived SiCN in both bulk and thin film form. Friction and wear evaluations were made on bulk materials and thin films using a Si3N4 ballon-disk linear wear tester at various contact pressures and in different environments that contained various amounts of humidity. The micro/nanostructure was characterized by FTIR, microRaman, and scanning electron microscopy. Bulk SiCN gave a low friction coefficient and good wear resistance in humid environments but showed significant fracture and gouging in dry environments at higher contact pressures. Although there is ambiguity regarding the tribology of the thin films there seems to be a dependence upon the nitrogen content within the materials derived from the polymeric stage. The future work will focus on optimizing processing conditions of thin films and investigating the role that nitrogen plays in both bulk and thin film SiCN materials.

Friction Coefficients Measured at Lubricated Planar Contacts During Start-Up

1988 ◽  
Vol 110 (3) ◽  
pp. 533-538 ◽  
Author(s):  
E. H. Gassenfeit ◽  
A. Soom
Keyword(s):  
Static Friction ◽  
Transient Behavior ◽  
Molybdenum Disulphide ◽  
Friction Behavior ◽  
Friction Characteristic ◽  
Friction Coefficients ◽  
Motion Data ◽  
Start Up ◽  
Planar Contact ◽  
Lubrication Conditions

Measurements of instantaneous coefficients of friction and associated motions during start-up at a planar contact are presented for four different lubrication conditions. The various patterns of transient behavior are discussed. Difficulties in interpreting static friction coefficients during rapidly applied tangential loads are described in relation to the motion data. It is shown that a molybdenum disulphide grease yields a friction characteristic that is quite different from either dry or boundary lubricated conditions in the presence of liquid lubricants. Transition distances from a static or maximum initial friction to kinetic conditions are examined and found to be considerably longer than had been previously found for concentrated contacts. Some suggestions regarding future studies of unsteady friction behavior are made.

Influence of TiN particles on the wear behavior of silicon nitride–based composites

2004 ◽  
Vol 19 (2) ◽  
pp. 542-549 ◽  
Author(s):  
Chien-Cheng Liu ◽  
Jow-Lay Huang
Keyword(s):  
Electron Microscopy ◽  
Silicon Nitride ◽  
Friction And Wear ◽  
Wear Behavior ◽  
X Ray Diffraction ◽  
Friction Coefficients ◽  
A Value ◽  
Transmission Electron ◽  
Ceramic Components ◽  
Aisi 52100 Steel

The friction and wear behavior of Si3N4-based composites against AISI-52100 steel were investigated in the ball-on-disk mode in a nonlubrication reciprocation motion. It has been found that under the conditions used, all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10−8 and 1.389 × 10−6 mm3/N · m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients were reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09 × 10−8 and 0.32 × 10−6 mm3/ N · m at room temperature. All materials and worn surfaces as well as wear debris were investigated by means of scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and transmission electron microscopy (TEM) before or after the tribological tests. The TEM micrographs of wear track revealed plastic deformation through twins and cracking along grain boundary which play an important role in the fracture mechanism.

A Micro-Tribotester for Evaluating Friction and Wear on Side Contacting Surfaces in Bulk-Microfabricated Devices

2005 ◽  
Author(s):  
Zhanshe Guo ◽  
Yonggang Meng ◽  
Hao Wu ◽  
Caijun Su ◽  
Shizhu Wen
Keyword(s):  
Resonant Frequency ◽  
Friction And Wear ◽  
Fem Analysis ◽  
Elastic Displacement ◽  
Dynamic Friction ◽  
Bulk Silicon ◽  
Friction Coefficients ◽  
Lateral Contact ◽  
Silicon Materials ◽  
Contact Surfaces

A micro-tribotester has been designed and fabricated to evaluate friction and wear on lateral contact surfaces of silicon materials. In the design of the tribotester, FEM analysis was used to find the resonant frequency and elastic displacement of the device under electrostatic excitations. The micro-tribotester was fabricated with a standard bulk silicon process. Static and dynamic friction tests were done on the fabricated device under various DC and AC stimulation conditions. From the measured maximum deflections of the detecting beams in the loading and sliding directions, static and dynamic friction coefficients of contacting sidewalls have been obtained. Characteristics of tribological behaviors in MEMS were discussed.

Frictional Layer and Its Antifriction Effect in High-Purity Ti3SiC2 and TiC-Contained Ti3SiC2

2007 ◽  
Vol 280-283 ◽  
pp. 1347-1352 ◽  
Author(s):  
Hong Xiang Zhai ◽  
Zhen Ying Huang ◽  
Yang Zhou ◽  
Zhi Li Zhang ◽  
Yi Fan Wang
Keyword(s):  
Friction Coefficient ◽  
High Purity ◽  
Friction And Wear ◽  
Low Carbon Steel ◽  
Normal Pressure ◽  
Layer By Layer ◽  
Low Carbon ◽  
Friction Surfaces ◽  
Wear Tests ◽  
Friction And Wear Tests

Characteristics of the frictional layer in high-purity Ti3SiC2 and TiC-contained Ti3SiC2, sliding against low carbon steel, were investigated. The friction and wear tests were made using a block-on-disk type friction tester with sliding speed of 20 m/s and several normal pressures from 0.1 MPa to 0.8 MPa. It was found that all friction surfaces, whether high-purity Ti3SiC2 or TiC-contained Ti3SiC2, were covered by a layer consisting of the oxides of Ti, Si and Fe. The layer was sticky, superimposed layer-by-layer, and the compact was increased with the normal pressure increasing. Because its antifriction effect, the friction coefficient decreases from the maximum 0.35 to 0.27 with increase in the normal pressure from 0.2 MPa to 0.8 MPa for the high-purity Ti3SiC2, and decreases from the maximum 0.55 to 0.37 for the same change of the normal pressure for the TiC-contained Ti3SiC2. The contained TiC grains had effects on the stickiness, liquidness, as well as the morphology of the layer, and induced the friction coefficient to increase in the entire level.

Unlubricated Sliding Wear of TiN Particle Reinforced Si3N4 Matrix Composites Against AISI-52100 Steel Ball

2007 ◽  
Vol 280-283 ◽  
pp. 1327-1330
Author(s):  
Chien Cheng Liu ◽  
Jow Lay Huang
Keyword(s):  
Friction And Wear ◽  
Wear Behavior ◽  
Matrix Composites ◽  
Wear Properties ◽  
Low Friction ◽  
Friction Coefficients ◽  
A Value ◽  
Aisi 52100 ◽  
Ceramic Components ◽  
Aisi 52100 Steel

The effects of TiN addition to Si3N4 on its mechanical and wear properties were investigated. The size and content of TiN particles were found having effects on the strength and toughness of Si3N4-based composites. The friction and wear behavior of Si3N4 based composites against AISI-52100 steel were investigated in the ball -on- disc mode in a non-lubrication reciprocation motion. It has been found that under the conditions used all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10-8 and 1.389 × 10-6 mm3/N.m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients was reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09×10-8 and 0.32×10-6 mm3/N.m at room temperature.

Novel Formulation of the Tightening and Breakaway Torque Components in Threaded Fasteners

2006 ◽  
Author(s):  
Sayed A. Nassar ◽  
Xianjie Yang
Keyword(s):  
Contact Pressure ◽  
Static Friction ◽  
Bolted Connections ◽  
Friction Coefficients ◽  
Difference Analysis ◽  
Threaded Fasteners ◽  
Thread Profile ◽  
Percent Difference ◽  
Breakaway Torque ◽  
Torque Values

New formulas are developed for the torque-tension relationship, various torque components, and for the break-away torque values in threaded fastener applications. The 3-D aspects of the lead helix and thread profile angles, the kinetic and static friction coefficients are all taken into account. Two scenarios of the contact pressure between threads and under the turning fastener head are considered; namely, uniform distributed and linearly distributed contact pressure scenarios. The effect of thread pitch, lead helix and thread profile angles, friction coefficients, and the fastener geometry is discussed. Results from the new formulas are compared with the approximate torque-tension relationship provided in the literature. A percent difference analysis indicates that the new formulas provide significant improvement that would enhance the reliability and safety of bolted connections, especially in critical applications.

Lubricant Performance in Magnetic Thin Film Disks With Carbon Overcoat—Part I: Dynamic and Static Friction

1991 ◽  
Vol 113 (1) ◽  
pp. 22-31 ◽  
Author(s):  
J. L. Streator ◽  
B. Bhushan ◽  
D. B. Bogy
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Static Friction ◽  
Disk Surface ◽  
Stick Slip ◽  
Sliding Speed ◽  
Friction Coefficients ◽  
Friction Forces ◽  
Strong Adhesion ◽  
Lubricant Viscosity

Static and dynamic friction coefficients are presented for an Al2O3·TiC slider in contact with 130 mm carbon-coated rigid thin film disks lubricated with several different perfluoropolyether lubricants. The lubricants tested include three nonpolar liquid lubricants and one polar liquid lubricant with dihydroxyl end groups. The effects of lubricant film thickness, disk surface topography, sliding speed and lubricant viscosity are investigated. In many cases, the interfaces exhibited a sharp increase in the dynamic and static friction coefficients after a certain film thickness was reached, due to strong adhesion in the interface. In most cases, the lubricant thickness for the onset of high friction forces was found to increase with increasing disk surface roughness, lubricant viscosity and sliding speed. Under certain conditions stick/slip of the slider occurred during which the static friction increased with time of contact. The various data suggest that the rate at which strong adhesion develops depends on the lubricant viscosity.

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