Enhancement of Wear Resistance of Copper With Tungsten Addition (≤20 wt %) by Powder Metallurgy Route

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Poulami Maji ◽  
R. K. Dube ◽  
Bikramjit Basu
Keyword(s):  
Wear Resistance ◽  
Wear Rate ◽  
Electrical Contacts ◽  
Operating Conditions ◽  
Fretting Wear ◽  
Wear Loss ◽  
Composite Surface ◽  
The Coefficient Of Friction ◽  
Improved Performance ◽  
Pure Cu

Copper–tungsten composite materials are developed for applications such as electrical contacts, resistance electrodes, and contact tips in welding guns as well as for components requiring higher wear resistance. In addition to the aspect of improved performance, it is scientifically interesting to assess the tribological properties, and therefore the objectives of the present work include, to determine the role of W additions in improving the fretting wear resistance of Cu for electrical applications, to determine the optimum concentration for W additions, and to identify the mechanisms responsible for fretting wear improvements. In addressing these issues, a planned set of fretting wear tests were conducted on powder metallurgically processed Cu–W composites (maximum W content of 20 wt %) against steel counterbody under varying load (up to 10 N) for 10,000 cycles. It has been observed that at lower loads of 2 N, the coefficient of friction (COF) recorded was ∼0.9 for the Cu–20 wt % W/steel, whereas it was ∼0.85 for a pure Cu/steel couple. Under similar operating conditions with the increase in load, the COF decreases to 0.5 at 10 N load, irrespective of the composition of the Cu–W composite. Furthermore, the incorporation of 5 wt % W has reduced the volumetric wear loss by 4–6 folds in comparison to unreinforced Cu. The addition of even higher percentage of W has led to increase its wear resistance by ∼10 folds. Under the investigated conditions, the wear rate systematically decreases with the increase in load for all the tested Cu–W composites. Based on the topographical observation of worn surfaces, it is observed that wear mechanisms for the Cu and Cu–W composites are tribochemical wear, adhesive wear, and abrasive wear. The incorporation of harder W particles (5 wt % or more) help in abrading the steel ball and in forming a dense tribolayer of FexOy, which effectively reduces wear rate and hence, increases wear resistance of the Cu–W composite surface in reference to unreinforced Cu.

scholarly journals Effects of Microstructure Evolution on Fretting Wear Behaviors of 25CrNi2MoVE Steel under Different Tempering States

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 351
Author(s):  
Xiongfeng Hu ◽  
Fuqiang Lai ◽  
Shengguan Qu ◽  
Yalong Zhang ◽  
Haipeng Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Wear Rate ◽  
Wear Mechanisms ◽  
Adhesive Wear ◽  
Operating Conditions ◽  
Fretting Wear ◽  
Fatigue Wear ◽  
Tempering Temperature ◽  
Worn Surface

Increasing load requirements and harsh operating conditions have worsened the wear of drive shafts in special field vehicles. In this paper, the evolution of the microstructure and fretting wear behaviors of 25CrNi2MoVE torsion shaft steel and their influence on the wear mechanisms were investigated as a function of tempering temperature. The results showed that the coarse grain size, low matrix hardness and non-metallic inclusions in the as-received state lead to a high wear rate and serious adhesive wear. The grain refinement after normalizing and the formed M5C2 carbide and bainite helped to improve the wear resistance and worn surface quality. Low temperature tempering is conducive to further improve the wear resistance of normalized samples, and the wear rate and worn surface roughness are increased gradually after tempering temperature increases. For quenching, although martensite structure can achieve a lower wear rate, the coefficient of friction is much higher; the wear mechanisms are primarily fatigue wear and adhesive wear. Although the adhesive wear degree and worn surface roughness were increased, the optimal anti-wear performances are obtained under tempering at 350 °C with good continuity of the surface oxide film. Excessive tempering temperature will make the softened matrix unable to form a beneficial “third-body wear”.

scholarly journals Fretting wear rate of sulphur deficient MoSx coatings based on dissipated energy

2001 ◽  
Vol 16 (12) ◽  
pp. 3567-3574 ◽  
Author(s):  
Xiaoling Zhang ◽  
W. Lauwerens ◽  
L. Stals ◽  
Jiawen He ◽  
J-P. Celis
Keyword(s):  
Relative Humidity ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Contact Stress ◽  
Ambient Air ◽  
Fretting Wear ◽  
Dissipated Energy ◽  
Wear Volume ◽  
The Coefficient Of Friction ◽  
Crystallographic Orientations

The fretting wear of sulphur-deficient MoSx coatings with different crystallographic orientations has been investigated in ambient air of controlled relative humidity. The coefficient of friction and the wear rate of MoSx coatings sliding against corundum depend not only on fretting parameters like contact stress, fretting frequency, and relative humidity, but also strongly on the crystallographic orientation of the coatings. For randomly oriented MoSx coatings, the coefficient of friction and the wear rate increased significantly with increasing relative humidity. In contrast, basal-oriented MoSx coatings were less sensitive to relative humidity. The coefficient of friction of both types of MoSx coatings decreased on sliding against corundum with increasing contact stress and decreasing fretting frequency. A correlation between dissipated energy and wear volume is proposed. This approach allows detection in a simple way of differences in fretting wear resistance between random- and basal-oriented MoSx coatings tested in ambient air of different relative humidity.

Fretting Wear of SiC and Ni3Al Particles Reinforced Al Alloy Matrix Composites

2007 ◽  
Vol 351 ◽  
pp. 75-80
Author(s):  
Rong Chen ◽  
Hong Hua Wang ◽  
Di Zhang ◽  
Guo Ding Zhang
Keyword(s):  
Wear Resistance ◽  
Aluminum Alloy ◽  
Friction And Wear ◽  
Al Alloys ◽  
Fretting Wear ◽  
Al Alloy ◽  
Wear Depth ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
The Coefficient Of Friction

Fretting friction and wear of aluminum alloy, 5 and 10 vol.% SiCp/Al and Ni3Alp/Al composites under 5×10-4 Pa and atmosphere was investigated. Wear mechanism in vacuum was compared to that in atmosphere at different applied loads. The coefficient of friction (COF) of the SiCp/Al composites was larger than aluminum and Ni3Alp/Al composites, however, incorporation of SiC particles into Al alloy increased the fretting wear resistance of Al alloys, especially in vacuum. It should be notices that the maximum wear depth was larger in vacuum under fretting wear, and the Ni3Alp/Al composites show low fretting wear resistance.

Tribological Investigations of Parts Sintered and Coated by Laser Beam

2005 ◽  
Vol 473-474 ◽  
pp. 255-260 ◽  
Author(s):  
T. Sebestyén ◽  
Gábor Buza ◽  
F. Franek ◽  
János Takács ◽  
Zoltán Kálazi ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Steel Substrate ◽  
Laboratory Model ◽  
Reinforced Polymers ◽  
The Coefficient Of Friction ◽  
Glass Fibre Reinforced ◽  
Pin On Disk ◽  
Short Carbon

In this work we intend to investigate the surface properties of laser sintered and coated parts, by measurement of friction coefficient and wear rate. The main aim of this research is to justify laser sintered prototype tools for injection molding of fibre-reinforced polymers. For increase of wear resistance we used hard Co-based and Fe-based coatings on laser-sintered phosphorous bronze and unalloyed steel substrate. Short carbon- and glass-fibre-reinforced polymers were used as counter bodies. For the tribological laboratory model tests a pin-on-disk test rig was used. In case of coated parts – with higher wear resistance – we used a cylinder-on-cylinder tribometer. The tribological properties were determined at different load conditions. Our results show that the friction coefficient and wear resistance of laser treated surfaces are good. The coefficient of friction of coated specimens is slightly less, but the wear rate is significantly less.

scholarly journals Effect on Microstructure and Performance of B4C Content in B4C/Cu Composite

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1250
Author(s):  
Dayu Shu ◽  
Xiuqing Li ◽  
Qingxia Yang
Keyword(s):  
Wear Resistance ◽  
Discharge Plasma ◽  
Pure Copper ◽  
Mechanical Mixing ◽  
Composite Surface ◽  
Plasma Sintering ◽  
And Performance ◽  
Pure Cu ◽  
Boron Carbide B4c ◽  
Microstructure And Performance

In this paper, boron carbide (B4C) ceramics were added to a copper (Cu) base, to improve the mechanical properties and wear resistance of pure copper. The B4C/Cu composites with different B4C contents, were obtained by mechanical mixing and discharge plasma sintering methods. Scanning electron microscopy (SEM), energy spectrum analysis (EDS), and electron probe microanalysis (EPMA) were used, to observe and analyze the microstructures of the B4C/Cu composites. The influences of the B4C content on the hardness, density, conductivity, and wear resistance were also studied. The experimental results show that B4C has an important effect on Cu. With increasing B4C content, both the density and conductivity of the B4C/Cu composites gradually decrease. The hardness of the Cu-15 wt.% B4C composite has the highest value, 86 HBW (Brinell hardness tungsten carbide ball indenter), which is 79.2% higher than that of pure copper. However, when the B4C amount increases to 20 wt.%, the hardness decreases due to the metallic connection being weakened in the material. The Cu-15 wt.% B4C composite has the lowest volume loss, indicating that it has the best wear resistance. Analyses of worn B4C/Cu composite surfaces suggest that deep and narrow grooves, as well as sharp ridges, appear on the worn pure Cu surface, but on the worn Cu-15 wt.% B4C composite surface, the furrows become shallow and few. In particular, ridge formation cannot be found on the worn Cu-15 wt.% B4C composite surface, which represents the enhancement in wear resistance.

Modelling the tribological response in dry sliding of boron modified as-cast Ti6Al4V on hardened steel

2021 ◽  
pp. 135065012110592
Author(s):  
Palash Roy Choudhury ◽  
Korimilli Eswar Prasad ◽  
John K. Schueller ◽  
Abhijit Bhattacharyya
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Boron Content ◽  
Normal Load ◽  
Operating Conditions ◽  
Dry Sliding ◽  
Contour Plots ◽  
The Coefficient Of Friction ◽  
En 31 ◽  
Full Factorial

Tribological characteristics of boron modified as-cast Ti6Al4V alloys are not very well known, but these alloys enjoy improved as-cast mechanical properties and favourable manufacturing economy. Experimental results are reported here for the effects of sliding speed and normal load on the wear rate and the coefficient of friction in dry sliding of these alloys on hardened EN 31 steel. Alloys having 0%, 0.30%, and 0.55% boron by weight were tested. A full factorial experiment assessed the effects of boron content, speed, and load on wear and friction. Interactions between speed and load were found to be statistically significant in influencing the wear rate and the coefficient of friction. Regression models are developed to predict the wear rate and coefficient of friction responses. The developed contour plots can assist designers in choosing operating conditions when selecting these alloys even if the wear mechanisms are unknown. Evidence shows that the wear resistance of Ti6Al4V can be improved by boron addition, and wear regimes are sensitive to boron content.

scholarly journals Experimental and Analytical Investigations on Tribological Properties of PTFE/AP Composites

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4295
Author(s):  
Hai Wang ◽  
Annan Sun ◽  
Xiaowen Qi ◽  
Yu Dong ◽  
Bingli Fan
Keyword(s):  
Wear Resistance ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Chemical Structure ◽  
Element Composition ◽  
Support Material ◽  
Test Conditions ◽  
Transfer Films ◽  
The Coefficient Of Friction

The tribological properties of polytetrafluoroethylene (PTFE)/AP (poly(para-phenyleneterephthalamide) (PPTA) pulp) composites under different test conditions (load: 2N, 10N; frequency: 1 Hz, 4 Hz; amplitude: 2 mm, 8 mm) were holistically evaluated. PTFE/AP composites with different AP mass ratios of 3%, 6%, and 12% as a skeleton support material were prepared. The coefficient of friction (COF) and wear rate were determined on a ball-on-disk tribometer. Furthermore, the morphology, element composition, and chemical structure of the transfer membrane were analyzed accordingly. The relationships between load, frequency, amplitude, and tribological properties were further investigated. According to the wear mechanism, AP enables effective improvement in the stiffness and wear resistance, which is also conducive to the formation of transfer films.

Tribological evaluation of piston ring/cylinder liner assembly in automotive engines using GNP as a lubricant additive

2021 ◽  
pp. 095440622110553
Author(s):  
Gurtej Singh ◽  
Mohammad Farooq Wani ◽  
Mohammad Marouf Wani
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Piston Ring ◽  
Film Formation ◽  
Cylinder Liner ◽  
Lubricant Additive ◽  
Operating Conditions ◽  
Power Losses ◽  
Automotive Engines ◽  
The Coefficient Of Friction

Friction and wear are the main causes of energy dissipation in automotive engines. To minimize the frictional power losses, it is extremely important to improve the tribological characteristics of ring/liner assembly which accounts for almost 40–50% frictional power losses. The present study attempts to mitigate friction and wear of the ring/liner tribo-pair using GNP/SAE 15W40 nano-lubricant. To simulate the ring/liner interface, the tribological performance of nano-lubricants was assessed using a tribometer based on ASTMG181 standard under various operating conditions. The coefficient of friction (COF) and wear rate lowered using graphene nano-lubricants (GNL). The tribological results showed that friction coefficient, wear rate, and surface roughness of piston ring improved in the range 17.71%–42.33%, 25%–40.62%, and 61%, respectively, under GNL lubricating conditions during the boundary lubrication. Further, the characterization of wear tracks of piston ring and cylinder liner confirmed tribo-film formation on worn surfaces resulting in decreased COF and wear rate.

The Effect on the Dry Sliding Wear Behavior of Gravity Cast A357 Reinforced with Dual Size Silicon Carbide Particles

2016 ◽  
Vol 829 ◽  
pp. 83-89 ◽  
Author(s):  
L. Avinash ◽  
T. Ramprabhu ◽  
Srikanth Bontha
Keyword(s):  
Wear Resistance ◽  
Wear Rate ◽  
Transition Period ◽  
Wear Behavior ◽  
Cast Alloy ◽  
Dry Sliding Wear ◽  
Wear Loss ◽  
A357 Alloy ◽  
Severe Wear ◽  
Sliding Distance

In the present study, the composites of A357 (Al-7%Si) alloy reinforced with the bimodal sizes (~250µm (L) and ~38 µm (S)) of 6wt% SiCp and the A357 alloy were prepared by permanent mould die casting. Three different combinations of bimodal distributions were considered: (3% L + 3% S, 4% L + 2% S, and 2% L + 4% S). The wear behavior of the alloy and the composites was studied for the speed of 1 m/s and load conditions of 10-30 N with an interval of 5 N in a pin on disc apparatus. The hardness and microstructure of the composites were also characteristised. The results suggest that the addition of bimodal size of particles significantly improves the hardness and wear resistance of the alloy. Among the different combinations, the 4% L + 2% S bimodal distribution combination provides the highest wear resistance and the hardness. This result indicates that the higher amount of large size particles are more important than that of small size particles to improve the wear resistance, which implies that the particle decohesion is the rate controlling step in the present investigation. The wear rate increases with an increase of load and sliding distance. The critical load to enter into the severe wear regime for the alloy and composites is 25 N. The rapid wear loss begins above 1500 m sliding distance in the composites and the as cast alloy. The wear rate curve with respect to the sliding distance shows three regimes (1) transition period (2) steady state (3) severe wear state. The wear morphology studies show that the abrasive wear is the main wear mechanism in the bimodal size composites whereas the delamination wear is predominant in the alloy.

scholarly journals Tribological Properties of Sputter Deposited Carbon-Copper Composite Films

2015 ◽  
Author(s):  
A. Leitans ◽  
N. Bulaha ◽  
J. Lungevics
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Magnetron Sputtering ◽  
Composite Coatings ◽  
Composite Films ◽  
Percentage Composition ◽  
The Coefficient Of Friction ◽  
Sputter Deposited ◽  
Copper Composite

Carbon-copper composite coatings were deposited using high power magnetron sputtering technique. Tribological tests were performed using ball-on-disk type tribometer. Friction coefficient and wear rate were determined at 40 N load. It was found that an increase in the percentage composition of carbon in C-Cu coating, reduces the coefficient of friction value. But at higher concentrations of C coating it becomes more brittle, that reduces wear resistance.

Sign in / Sign up

Export Citation Format

Share Document