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

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

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

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

Heat transfer performance of sintered Cu microchannels produced by a novel method

Microchannels have many thermal management applications due to their high heat transfer performance. In this paper, sintered Cu microchannels with well controlled channel diameters of 450 µm, 390 µm and 290 µm, and volume fractions of channels of 0.1, 0.2, 0.3 and 0.4, were manufactured by a new method and their pressure drops and heat transfer coefficients were compared with conventional machined Cu microchannel and porous Cu manufactured by Lost Carbonate Sintering (LCS). The pressure drops of the sintered Cu microchannels were higher than a conventional machined microchannel, but significantly lower than LCS porous Cu samples. The sintered Cu microchannels achieved a similar range of heat transfer coefficients as the LCS porous Cu, with much lower volume fractions of channels. They had higher heat transfer coefficients than the conventional machined microchannel, mainly due to the introduction of multilayers of channels in the metal matrix. Darcy-Weisbach and Sieder-Tate equations with the introduction of appropriate correcting factors can be used to estimate the pressure drop and heat transfer coefficient of the sintered Cu microchannels. There exists a strong correlation between heat transfer coefficient and pumping power