| The effects of powder size, heating rate, and sintering time on dimensional change, oil impregnation, radial crushing strength, and microstructure were examined in sintered Cu-10% Sn mixture. The copper powder sizes were -150 mesh and -270 mesh, and tin powders were -230 +325 mesh and -400 mesh. The specimens were sintered in hydrogen-nitrogen atmosphere at 797℃ for sintering time up to 15 minutes. The dimensional change of Cu-Sn mixture compacts occurred mostly during the heating up stage. Larger powder size, in particular, larger tin powder size and faster heating rate caused more expansion. The oil impregnation and radial crushing strength changed in a way similar to the density change. The observed dependence of growth on particle size and heating rate can be explained by densification effects of the solid state and liquid state sintering and the growth due to the penetration of copper particle boundaries by tin rich melt. The specimen of fine powder mixture sintered for 15 minutes showed uniform bronze structure with large grains. The practical implications of the present results are discussed. |
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