The effects of powder size and heating rate on various properties of sintered Cu-10% Sn was investigated. Experiments were carried out on four combinations of copper and tin powder sizes by mixing copper powders of -150 mesh and -270 mesh with -230 - +325 mesh and -400 mesh tin powders. The sintering temperatures were 797℃ and 807℃ with sintering times ranging from 0 to 15 minutes.
Generally the growth of Cu-Sn compacts occurred within the first 1 minute of sintering with subsequent slow shrinkage. The growth was largely dependent on the size of tin powder with larger growth occurring for larger tin powder size.
Faster heating rate caused larger growth. The observed dependence of growth of particle size and heating rate can be most consistently explained by the penetration of tin-rich liquid phase into the copper particle boundaries.
The amount of open porosity as indicated by the amount of oil impregnation was larger for samples of larger the powder. Slow heating reduced the open porosity significantly while the total porosity is little affected.
Radial crushing strength was larger for fine tin powder samples.
Microstructures show that larger grain growth occurred around the pores which were originally tin particle site and the amount of tin rich phase decreased with fine powder size. Therefore, more uniform structures can be obtained with finer powders.
