Dry sliding behavior of HVOF WC-CoCr coated counterface against Cu-Sn and SiC-graphite composite materials

2020 ◽  
Vol 397 ◽  
pp. 125977 ◽  
Author(s):  
Priyadarshini Jayashree ◽  
Simone Turani ◽  
Giovanni Straffelini
2011 ◽  
Vol 233-235 ◽  
pp. 3057-3063 ◽  
Author(s):  
Yovial Mahyoedin ◽  
Jaafar Sahari ◽  
Andanastuti Mukhtar ◽  
Norhamidi Mohammad

This investigation gives attention on the rheology characteristics of polymer composites based on graphite and carbon black as fillers for further processing using an injection molding machine. In such a high solid loading system, the particles exhibit a very strong tendency toward agglomeration. This rapidly increases the viscosity of the mixture and decreases moldability. The presence of agglomerates in the mixture in particular may result in defect within the microstructure in the final product, even though it is sometime necessary in electrical conductivity. Composite materials in this study are polypropylene (PP) as matrix, and graphite (G) and carbon black (CB) as fillers, with a varied composition according to the percentage weight (% wt) of CB. Twin screw co-rotating extruder was used for mixing materials in order to achieve the best homogeneity of this compound. The measurement results obtained using capillary rheometer equipment showed that the addition of CB to the mixture of PP/G increase the viscosity of the materials, increase the activation energy and generally reduce the fluidity of composite materials. The value of the mixture viscosity increases with increasing the number of CB, reducing the ability of materials to be formed (moldability). Material viscosity, activation energy, fluidity and moldability shows how suitable the compound material to be processed by using injection molding machine.


Author(s):  
Hozumi Goto ◽  
Yusaku Shibuya

Wear characteristics of an Al-Si alloy impregnated graphite composite containing 56 vol% graphite and its matrices in contact with bearing steel were investigated under insufficient lubrication. Pin-on-disk type wear tests in air were conducted at various levels of relative humidity (RH) under dry sliding and drip feed lubrication (0.005 to 0.02 cm3) before each test by using base oil for engines. Changes in friction and wear were continuously monitored during the tests. Four types of wear mode for the composite were obtained: steady wear with a low rate (Type 1), high wear after a lubricating oil shortage (Type 2), no wear after pin lifting (Type 3) and steady wear with a high rate (Type 4). Type 1 appears over the whole range of RH (5 to 80%). Type 2 is found at low RH levels of 5 and 10%. Type 3 occurs at a frequency of 30 percents between 10 and 35% RH. Type 4 is seen over the whole RH range under dry sliding. The appearance of each wear mode at a specified RH depends on wear behavior of the matrices associated with RH under drip feed lubrication.


Wear ◽  
2021 ◽  
Vol 464-465 ◽  
pp. 203553
Author(s):  
Priyadarshini Jayashree ◽  
Simone Turani ◽  
Giovanni Straffelini

1991 ◽  
Vol 41 (3) ◽  
pp. 915-920 ◽  
Author(s):  
T.A Ezquerra ◽  
M Kulescza ◽  
F.J Baltá-Calleja

2016 ◽  
Vol 36 (3) ◽  
pp. 279-286
Author(s):  
Huseyin Unal ◽  
Ugur A. Kaya ◽  
Kadir Esmer ◽  
A. Mimaroglu ◽  
Bayram Poyraz

Abstract In this study, the influence of wax content on the electrical, thermal and tribological properties of a polyamide 6 composite filled with 15% wt. graphite was investigated. The wax filler contents of the composite were by 2, 4 and 6 wt.%. Characterisation of the composites was obtained using a Fourier transform infrared spectroscopy test. Electrical performance tests were carried out, and the dielectric real values (ε′) and imaginary values (ε″) were recorded. Thermal differential scanning calorimetry tests were carried out, and the glassy and melting temperatures of the composite materials were recorded. Furthermore, tribological tests were carried out and the friction coefficient and wear rate of the composites were recorded. The results show that the increase in wax content led to the increase in the permittivity values (ε′ and ε″) of the composites. The increase in wax content also led to the decrease in the friction coefficient and wear rates of the composite materials. Furthermore, the glassy and melting temperatures of the composite materials showed a sensitivity to the wax content. Finally, it is concluded that optimum properties, in total, were obtained in the composite filled with 6 wt.% wax.


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