To attain new pantograph skateboard with high strength-toughness and simple fabrication process, copper fiber and carbon fiber reinforced carbon-based composite (Cuf/Cf/C composite) was fabricated by hot pressing technology, micro-structure, mechanical and tribological performances were investigated and compared with the results of carbon skateboard. Cuf/Cf/C composite is superior to carbon skateboard in terms of compactness, hardness, electrical conductivity, mechanical strength and wear resistance. During sliding friction tests with electric current, mechanical acting wear and arc erosion have a stimulating circulation on the worn surface, and adding carbon fiber slows down the deteriorated wear cycle and improves wear resistance. High carbon crystallinity degree of the tribolayer presents low molecular acting friction force, and adjusting crystallite structure is essential to improve friction performance.
Copper impregnated carbon/carbon composite (Cu-C/C composite) was fabricated for novel sliding collector material by weaving carbon fiber, heat treatment and Cu alloy impregnation. The effects of counterpart materials (Fe ball and Cu ball) on friction and wear behaviors were investigated and compared with the result of carbon contact strip used in high-speed railway. Morphology, chemical composition, phase and structure of wear surface and tribolayer were characterized to clarify tribological mechanisms. The results show that friction coefficient follows the order: Cu-C/C composite/Cu ball > carbon contact strip/Fe ball > Cu-C/C composite/Fe ball > carbon contact strip/Cu ball. The carbon crystalline of wear surface appears preferred orientation along the sliding orientation, which is benefit for boundary lubrication. When the counterpart material is Fe ball, Cu-C/C composite is superior to pure carbon strip in mechanical strength, electrical conductivity, wear resistance and
Abstract
The effect of grain boundary (GB) defects on the tribological properties of MoS has been investigated by molecular dynamics (MD) simulations. The GB defects-containing MoS during scratching process shows a lower critical breaking load than that of indentation process, owing to the combined effect of pushing and interlocking actions between the tip and MoS atoms. The wear resistance of MoS with GB defects is relevant to the misorientation angle due to the accumulation of long Mo-S bonds around the GBs. Weakening the adhesion strength between the MoS and substrate is an efficient way to improve the wear resistance of MoS with low-angle GBs. 2 2 2 2 2 2