High-temperature resistivity of aluminum–carbon nanotube composites

• Published in: Journal of materials science Vol. 50; no. 21; pp. 7087 - 7096
• Main Authors: Genova, V, Gozzi, D, Latini, A
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2015; Springer; Springer Nature B.V
• Subjects: Aluminum; Aluminum carbide; Bulk density; Bulk sampling; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Composition; Crystallography and Scattering Methods; Cylinders; Density; Electric properties; Electrical resistivity; High temperature; High vacuum; Materials Science; Metal matrix composites; Multi wall carbon nanotubes; Nanostructure; Nanotubes; Original Paper; Polymer Sciences; Single wall carbon nanotubes; Sintering; Solid Mechanics; Temperature; Quadratic Fitting; Percolation Threshold; Aluminum Carbide; Metallic Matrix; Powder Metallurgy Route
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-015-9263-y

The resistivity and thermal coefficient of resistivity (TCR), of metallic matrix composites, MMCs, aluminum–carbon nanotube, Al-CNT, were studied under high vacuum in the temperature interval from RT to 800 K. The samples shaped as small cylinders and containing single-walled CNTs or multi-walled CNTs were sintered at 625 °C. The resistivity of sintered samples of pure Al was found three orders of magnitude higher with respect to bulk, having the former a density value equal to 98.8 % of bulk Al. The explored range of the CNT concentration was within 5 wt%. At the highest CNT concentrations, the trend of resistivity against temperature was found negative being more pronounced for composites with MWCNTs. For Al-SWCNT composites, at around 3.3 wt% (4.2 vol%), TCR is practically independent from temperature; for Al-MWCNT, the TCR zero-crossing occurs at different compositions depending on temperature. Higher is the temperature, lower is the TCR zero-crossing composition. Resistivity data were discussed in the framework of the Matthiessen’s rule and sound evidences were shown that no Al₄C₃ formation was detected at working temperatures.