High porosity micro- and macro-cellular copper foams with semi-open cell microstructure toward its physical and mechanical properties

Abstract

Herein, a powder compacting method was developed to fabricate high porosity micro- and macro-cellular copper foams using CaCO3 space holder. The cold compacted precursors were heated at different temperatures under the nitrogen atmosphere. The effects of precursor compaction pressure, space holder content and sintering temperature on cell microstructure, relative density, compressive and physical properties were investigated. The scanning electron microscopy (SEM) images showed a uniform distribution of interconnected pores with sizes of pores and channels less than 50 microns formed the semi-open cell structure of the fabricated foams. The evaluation of the foaming agent content, 0 to 20 (wt%), in precursor materials showed relatively large changes in the porosity percentage (27%–50%), with the utilitarian strength (43 MPa) and densification strain (40%) of the copper foams. For specimens having 20 wt% CaCO3, tuning the sintering temperature (600 °C) and compacting pressure (500 MPa) of precursors tailored superior porosity percent (47%), remarkable compressive stress (501 MPa) and high thermal (43.8 W m−1.k), and electrical conductivity (0.06 × 10 8 Ω−1 m−1) owing to a desirable foaming process. A massive gas release during the CaCO3 decomposition and the strengthened cell walls of the copper foams during the sintering resulted in the high porosity and strength of the fabricated foams. The presented fabrication method and our results are the core elements for the development of new high porosity metal foams that can help the development of the future application of copper foams for a long-life anode for lithium-ion batteries, catalysis, and thermal and electrical performances as electronic cooling materials.