Two kinds of Ag-graphite composites reinforced with spherical graphite(SG)and conventional flake graphite(FG)were prepared by powder metallurgy technology.The effect of graphite morphology on the tribological behavior...Two kinds of Ag-graphite composites reinforced with spherical graphite(SG)and conventional flake graphite(FG)were prepared by powder metallurgy technology.The effect of graphite morphology on the tribological behavior for the Ag-SG and Ag-FG under the dry sliding wear was investigated with a pin-on-disk tribometer at a load of 3.0 N in atmosphere condition.The results indicated that the minimum wear rate of 3.5×10^-5 mm^3/(N·m)for Ag-FG was achieved and it reduced by nearly an order of magnitude,reaching 1.6×10^-6 mm^3/(N·m)for the Ag-SG.The obviously different tribological behaviors between the Ag-SG and Ag-FG were closely related to the formation of cracks in the sub-surface.The stress concentration tended to generate at the edges of flake graphite during sliding process,which resulted in the cracks and severe delamination wear of Ag-FG.However,no cracks were found around the spherical graphite in Ag-SG.The spherical graphite can effectively inhibit the initiation and propagation of cracks,achieving high wear resistance.展开更多
基金Project(51674304)supported by the National Natural Science Foundation of ChinaProject(2018JJ3677)supported by Natural Science Foundation of Hunan Province,China。
文摘Two kinds of Ag-graphite composites reinforced with spherical graphite(SG)and conventional flake graphite(FG)were prepared by powder metallurgy technology.The effect of graphite morphology on the tribological behavior for the Ag-SG and Ag-FG under the dry sliding wear was investigated with a pin-on-disk tribometer at a load of 3.0 N in atmosphere condition.The results indicated that the minimum wear rate of 3.5×10^-5 mm^3/(N·m)for Ag-FG was achieved and it reduced by nearly an order of magnitude,reaching 1.6×10^-6 mm^3/(N·m)for the Ag-SG.The obviously different tribological behaviors between the Ag-SG and Ag-FG were closely related to the formation of cracks in the sub-surface.The stress concentration tended to generate at the edges of flake graphite during sliding process,which resulted in the cracks and severe delamination wear of Ag-FG.However,no cracks were found around the spherical graphite in Ag-SG.The spherical graphite can effectively inhibit the initiation and propagation of cracks,achieving high wear resistance.
