Specific Surface Areas of Porous Cu Manufactured by Lost Carbonate Sintering: Measurements by Quantitative Stereology and Cyclic Voltammetry

摘要

Open-cell porous metals have many applications due to high surface area to volume ratios. Porous metals manufactured by the space holder methods have distinctively different porous structure from commercial open-cell metal foams, but very little research has been conducted to characterise the surface area of this class of materials. This paper measured the geometric, electroactive and real surface areas of porous Cu samples manufactured by the Lost Carbonate Sintering process by quantitative stereology and cyclic voltammetry. A cyclic voltammetry (peak current) procedure has been developed and successfully applied to the measurement of electroactive surface areas of the porous Cu. For porous Cu samples with pore sizes 75-1500 µm and porosities 0.5-0.8, the volumetric and gravimetric specific geometric, electroactive and real surface areas are in the ranges of 15-90 cm-1 and 5-45 cm2/g, 200-400 cm-1 and 40-130 cm2/g, and 1000-2500 cm-1 and 400-800 cm2/g, respectively, varying with pore size and porosity. The geometric, electroactive and real surface areas are found to result from the contributions from primary porosity, primary and secondary porosities, and surfaces of metal particles, respectively. The measurement methods adopted in this study can provide vital information of surface areas at different length scales, which is important for many applications.