Pulsed electric current sintering of Cu matrix composites reinforced with plain and coated alumina powders

• Cu/Al2O3 composites with 30 to 60 vol.% alumina are fabricated by (PECS).
• The alumina phase behaves like a barrier for the free flow of the plastic matrix.
• The Cu-coated fillers eliminate the true Al2O3–Al2O3 contacts.
• Composites with densification higher to 97% are possible below 60% Al2O3.
• Densification is always higher when using Cu-coated ceramics.

Cu/Al2O3 composites with Al2O3 fractions between 0.3 and 0.6 were sintered at 100 MPa under vacuum by pulse electric current sintering (PECS). The effect of the temperature and the ceramic content on the microstructure and densification of the composites was studied. The sintering behavior of mixtures prepared by the conventional blending of alumina and copper powders was compared with that of mixtures of copper with Cu-coated Al2O3 particles (18 vol.% Cu). The composites prepared by the coated filler method were slightly more densified than those made through the admixture method, a variation that became more pronounced with an increase in the ceramic content. The composites prepared by the admixture method showed a large number of Al2O3–Al2O3 contacts that prevented densification, forming interparticle pores. The coated filler materials enhanced the connectivity of the matrix and distribution of alumina, yielding Cu/Al2O3 composites with 98.5 to 96.7% densification when varying the ceramic content from 30 to 60 vol.%, respectively.

The effect of the temperature and the ceramic content on the microstructure and densification of Cu/Al2O3 composites prepared by pulse electric current sintering (PECS) was studied. The composites prepared by the coated filler method were slightly more densified than those made through the admixture method, variation that became more pronounced with an increase in the ceramic content.Figure optionsDownload as PowerPoint slide