Nanoparticles are increasingly being used to improve the friction and wear performance of polymers. In this study, we investigated the tribological behavior and energy dissipation characteristics of nano-Al_2O_3-reinf...Nanoparticles are increasingly being used to improve the friction and wear performance of polymers. In this study, we investigated the tribological behavior and energy dissipation characteristics of nano-Al_2O_3-reinforced polytetrafluoroethylenepolyphenylene sulfide(PTFE-PPS) composites in a sliding system. The tribological behaviors of the composites were evaluated under different normal loads(100–300 N) at a high linear velocity(2 m/s) using a block-on-ring tester. Addition of the nano-Al_2O_3 filler improved the antiwear performance of the PTFE-PPS composites, and the friction coefficient increased slightly. The lowest wear rate was obtained when the nano-Al_2O_3 content was 3%(volume fraction). Further, the results indicated a linear correlation between wear and the amount of energy dissipated, even though the wear mechanism changed with the nano-Al_2O_3 content, independent of the normal load applied.展开更多
A new method of manufacturing micro-flow channels on graphite composite bipolar plate(GCBPP) microplaning using specially designed multi-tooth tool is proposed. In this method, several or even dozens of parallel micro...A new method of manufacturing micro-flow channels on graphite composite bipolar plate(GCBPP) microplaning using specially designed multi-tooth tool is proposed. In this method, several or even dozens of parallel micro-flow channels ranging from 100 μm to 500 μm in width can be produced simultaneously. But, edge chippings easily occur on the rib surface of GCBPP during microplaning due to brittleness of graphite composites. Experimental results show that edge chippings result in the increase of contact resistance between bipolar plate and carbon paper at low compaction force. While the edge chippings scarcely exert influence on the contact resistance at high compaction force. Contrary to conventional view, the edge chippings can significantly improve performance of microfuel cell and big edge chippings outperform small edge chippings. In addition, the influence of technical parameters on edge chippings was investigated in order to obtain big, but not oversized edge chippings.展开更多
SiO2-Al2O3/EP-PU nanocomposites, which contained polyurethane(PU) flexible chain, were prepared via epoxy resin, PU and modified silica and alumina particles. Silica and alumina particles were modified by coupling age...SiO2-Al2O3/EP-PU nanocomposites, which contained polyurethane(PU) flexible chain, were prepared via epoxy resin, PU and modified silica and alumina particles. Silica and alumina particles were modified by coupling agents KH-560 and KH550, respectively. EP-PU was used as matrix, PU as toughening agent, Si O2-Al2O3 as filled and MTHPA as curing agent. The mass ratio of PU was 30% in this system. The chemical structure of the products was confirmed by FT-IR measurements, the morphological structure of fracture surface and the surface of the hybrid materials were observed by scanning electron microscope(SEM) and transmission electron microscope(TEM), and shearing strength and breakdown field were measured, respectively. When the mass fraction of inorganic component was 10% and the mass ratio of Si O2 to Al2O3 was 4.5:5.5, shearing strength of Si O2-Al2O3/EP-PU was 28.5 MPa and breakdown field was 15 k V/mm, the data could meet the property requirement of insulating material.展开更多
基金Project(51165022)supported by the National Natural Science Foundation of ChinaProject(20122117)supported by the Lanzhou Science and Technology Bureau Foundation,ChinaProject(1310RJZA036)supported by the Natural Science Foundation of Gansu Province,China
文摘Nanoparticles are increasingly being used to improve the friction and wear performance of polymers. In this study, we investigated the tribological behavior and energy dissipation characteristics of nano-Al_2O_3-reinforced polytetrafluoroethylenepolyphenylene sulfide(PTFE-PPS) composites in a sliding system. The tribological behaviors of the composites were evaluated under different normal loads(100–300 N) at a high linear velocity(2 m/s) using a block-on-ring tester. Addition of the nano-Al_2O_3 filler improved the antiwear performance of the PTFE-PPS composites, and the friction coefficient increased slightly. The lowest wear rate was obtained when the nano-Al_2O_3 content was 3%(volume fraction). Further, the results indicated a linear correlation between wear and the amount of energy dissipated, even though the wear mechanism changed with the nano-Al_2O_3 content, independent of the normal load applied.
基金Project(51075155)supported by the National Natural Science Foundation of ChinaProject(2013ZZ017)supported by the Fundamental Research Funds for the Central Universities,China
文摘A new method of manufacturing micro-flow channels on graphite composite bipolar plate(GCBPP) microplaning using specially designed multi-tooth tool is proposed. In this method, several or even dozens of parallel micro-flow channels ranging from 100 μm to 500 μm in width can be produced simultaneously. But, edge chippings easily occur on the rib surface of GCBPP during microplaning due to brittleness of graphite composites. Experimental results show that edge chippings result in the increase of contact resistance between bipolar plate and carbon paper at low compaction force. While the edge chippings scarcely exert influence on the contact resistance at high compaction force. Contrary to conventional view, the edge chippings can significantly improve performance of microfuel cell and big edge chippings outperform small edge chippings. In addition, the influence of technical parameters on edge chippings was investigated in order to obtain big, but not oversized edge chippings.
基金Project(2012RFJGG006)supported by the Harbin Science and Technology Innovation Foundation,China
文摘SiO2-Al2O3/EP-PU nanocomposites, which contained polyurethane(PU) flexible chain, were prepared via epoxy resin, PU and modified silica and alumina particles. Silica and alumina particles were modified by coupling agents KH-560 and KH550, respectively. EP-PU was used as matrix, PU as toughening agent, Si O2-Al2O3 as filled and MTHPA as curing agent. The mass ratio of PU was 30% in this system. The chemical structure of the products was confirmed by FT-IR measurements, the morphological structure of fracture surface and the surface of the hybrid materials were observed by scanning electron microscope(SEM) and transmission electron microscope(TEM), and shearing strength and breakdown field were measured, respectively. When the mass fraction of inorganic component was 10% and the mass ratio of Si O2 to Al2O3 was 4.5:5.5, shearing strength of Si O2-Al2O3/EP-PU was 28.5 MPa and breakdown field was 15 k V/mm, the data could meet the property requirement of insulating material.
