scholarly journals Influence of Surface Finishing and Binder Phase on Friction and Wear of WC Based Hardmetals

2007 ◽  
pp. 2403-2406
Author(s):  
Koenraad Bonny ◽  
Patrick De Baets ◽  
Omer van der Biest ◽  
Jozef Vleugels ◽  
Bert Lauwers
2007 ◽  
Vol 561-565 ◽  
pp. 2403-2406 ◽  
Author(s):  
Koenraad Bonny ◽  
Patrick de Baets ◽  
Omer Van der Biest ◽  
Jef Vleugels ◽  
Bert Lauwers

At present, cobalt is the most commonly used binder material in tungsten carbide based hardmetals. Current research on sliding wear performance of these cemented carbides, however, reveals promising results for nickel binder as well. Test samples of WC-Co and WC-Ni hardmetals have been machined and surface finished by wire-EDM and grinding. From comparative dry sliding pin-on-plate experiments on wire-EDM’ed, ground and polished grades, correlations are derived between wear volume loss and friction on the one hand and contact pressure, sliding distance, binder phase and microstructure on the other hand. The lowest wear levels are encountered with polished cemented carbides. The EDM induced surface modification turns out to deteriorate wear resistance, especially during the running-in stage of sliding. These findings are in agreement with Xray diffraction measurements of the residual stress level in the WC phase.


Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 1127-1138 ◽  
Author(s):  
Fengjun Wei ◽  
Bingli Pan ◽  
Juan Lopez

Abstract A kind of carbon fabric/epoxy composite was successfully prepared with carbon fiber fabric as reinforced phase and epoxy resin as binder phase, then the nano-TiO2 and a hybrid system of TiO2/MWNTs was added into the carbon fabric/ epoxy composite matrix respectively to prepare a kind of nano-composite. The friction and wear properties of CF/EP composites under different load conditions have been studied in this article, during the study the effects of filler types and contents on the tribological properties were researched, at last the worn surfaces were investigated and the abrasion mechanism was discussed. The results showed that: whether filling the nano-TiO2 alone or mixing the TiO2/MWNTs, it was able to achieve a good effect on decreasing friction and reducing wear, and the optimum addition ratio of the nano-TiO2 particles was 3.0% , meanwhile 3.0% of nano-TiO2 and 0.4% of MWNTs could cooperate with each other in their dimension, and could show a synergistic effect on modifying the tribological properties of CF/EP composites, the coefficient of friction of the modified composites decreased by 20% and the wear life increased by more than 140% compared with that of pristine composite materials, in the process of friction and wear, the wear form of the composites materials varied from brittle rupture to abrasive wear gradually.


1988 ◽  
Vol 140 ◽  
Author(s):  
Jeffrey L. Spodnik ◽  
James J. Wert

AbstractThe effect of surface finish on the unlubricated sliding wear behavior of a 94% A12O3 ceramic material has been investigated using a reciprocatingright cylinder-on-flat tribometer. The surface finishes evaluated were produced using a combinationof SiC and diamond abrasive particles.Profilometry was employed to characterize surface topography and x-ray diffraction was used to determine the residual stress associated with each finishing process.The coefficients of friction and controlling wear mechanisms varied dramatically as the maximum asperity height was altered by different finishing techniques. Below a peak profile of 0.25 μm, the coefficient of friction varied between 0.60 and 0.75 due to preferential shearing of the siliceous binder phase which segregated at surfacial pores and grain boundaries. Binder adhesion in the sliding contact produced stick-slip frictional behavior. Surfaces with asperity heights in excess of 10 μin exhibited intergranularfracture or grain “pluck-out”. These surfaces contained minimal real areas of contact and yielded friction coefficients of 0.30 - 0.35. Removed alumina grains actedas hard abrasives in the contact zone and enhanced transgranular fracture by a lateral cracking mechanism. Evidence of crack propagation as a result of Mode II and Mode III shearloading was discovered at subsurface pore sites. The influences of microindentation hardness and fracture toughness are discussed in terms of their relative importances on the observed wear behavior.


Author(s):  
K. Bonny ◽  
P. De Baets ◽  
Y. Perez ◽  
S. Van Autre`ve ◽  
J. Van Wittenberghe ◽  
...  

From comparative dry sliding pin-on-plate experiments on distinctive WC-Co and WC-Ni cemented carbides, machined by grinding or wire-EDM, correlations are derived between wear rate, wear volume and coefficient of friction and contact load, sliding distance, microstructure and surface finish condition. The EDM induced surface modification turns out to deteriorate wear resistance, especially during the wear-in stage of sliding. These findings are in agreement with X-ray diffraction measurements of the residual stress level in the WC phase.


2007 ◽  
Vol 561-565 ◽  
pp. 2025-2028 ◽  
Author(s):  
Koenraad Bonny ◽  
Patrick de Baets ◽  
Omer Van der Biest ◽  
Jef Vleugels ◽  
Bert Lauwers

Tungsten carbide based hardmetals with cobalt binder phase are widely used in engineering industries for their excellent mechanical properties and outstanding wear performance. Reciprocative sliding wear behaviour of a number of WC-Co based hardmetal grades was investigated using a small-scale pin-on-plate tribometer. Test samples were manufactured by electro-discharge machining (EDM) with various surface finishing regimes. SEM topographies and cross-section views of the cemented carbides were obtained both before and after dry friction tests, revealing distinctive wear mechanisms. The generated wear loss was quantified topographically using surface scanning equipment. Wear debris particles were collected and examined by EDX and TEM analysis. Based on experimental results, the execution of consecutive gradually finer EDM cutting steps was found to considerably enhance wear performance. Furthermore, a significant influence of contact load, sliding movement duration, application of lubricant and wear debris formation on wear rate and friction was established.


2003 ◽  
Vol 18 (6) ◽  
pp. 1314-1324 ◽  
Author(s):  
Bikramjit Basu ◽  
Jozef Vleugels ◽  
Omer Van Der Biest

Engineering ceramics and cermets are widely used for demanding tribological applications. In this perspective, the objective of this paper was to understand the friction and wear behavior of some of the potential tribomaterials, e.g., ZrO2–30 vol% TiB2 composite, sialon–40 vol% TiB2 composite, TiB2-based cermet with 16 vol% Ni3(Al,Ti) binder, and monolithic TiB2 in fretting contacts. Wear tests on the TiB2-containing materials under dry unlubricated conditions (23–25 °C, 50–55% relative humidity) were performed against corundum on a ball-on-flat tribometer. The obtained friction and wear data were critically analyzed to investigate how the binder phase in TiB2 matrix influences the tribological performance. Furthermore, morphological investigations of the transfer layers on the worn surfaces were performed and the wear mechanisms discussed. X-ray photoelectron spectroscopy analysis of the worn surfaces in the monolithic TiB2/alumina revealed the pronounced transfer of mixed oxides containing TiO2 and B2O3 to the alumina counterbody and also indicated the transfer of alumina to TiB2 flat. Tribochemical reactions and abrasion along with the material transfer between the counterbodies were observed to play a major role in the wear of the fretting couples.


Author(s):  
D.I. Potter ◽  
M. Ahmed ◽  
K. Ruffing

Ion implantation, used extensively for the past decade in fabricating semiconductor devices, now provides a unique means for altering the near-surface chemical compositions and microstructures of metals. These alterations often significantly improve physical properties that depend on the surface of the material; for example, catalysis, corrosion, oxidation, hardness, friction and wear. Frequently the mechanisms causing these beneficial alterations and property changes remain obscure and much of the current research in the area of ion implantation metallurgy is aimed at identifying such mechanisms. Investigators thus confront two immediate questions: To what extent is the chemical composition changed by implantation? What is the resulting microstructure? These two questions can be investigated very fruitfully with analytical electron microscopy (AEM), as described below.


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