Effect of particle coating on the thermal response of mixtures of micro- and nano-aluminum particles with water

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• 作者：K. A. Trowell ; J. Wang ; Y. Wang ; Y. Yavor…
• 关键词：Ageing effect ; Aluminum–water reaction ; Energy carriers ; Hydrogen production ; Metal fuels ; Nanopowder
• 刊名：Journal of Thermal Analysis and Calorimetry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：127
• 期：1
• 页码：1027-1036
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Analytical Chemistry; Polymer Sciences; Inorganic Chemistry; Measurement Science and Instrumentation;
• 出版者：Springer Netherlands
• ISSN：1588-2926
• 卷排序：127

文摘

Differential scanning calorimetry is used to determine the thermal response of commercially available aluminum powders reacting with an excess of water. Thermal response as a function of ageing, particle coating and heating rate is examined. The effect of the surface-to-volume ratio of the reaction vessel is also examined through the use of a purpose-built ignition apparatus. The work is motivated by the use of metal–water reactions to generate gaseous hydrogen for energy applications. Four powders are considered: nanopowder with preexisting oxide coating (U-ALEX), Viton®-coated nanopowder (V-ALEX), nonadecyclic-acid-coated nanopowder (L-ALEX) and oxide-coated micron-sized powder (H-2). The powder is mixed with water prior to testing, facilitated by ultrasonic agitation or the addition of a surfactant as needed. To determine the effect of ageing on the reaction onset temperature, selected samples are aged for 0, 1, 2, 5 and 14 days before being subjected to heat. The lowest and highest reaction onset temperatures were observed for the U-ALEX and L-ALEX powder mixtures, respectively. Coated powders had higher onset temperatures. The coatings offered some protection from oxidation, whereas the uncoated samples oxidized completely within 48 h. H-2, U-ALEX and V-ALEX exhibited similar activation energies and showed a slight decline in reaction onset temperature with ageing. It was not possible to determine an activation energy for L-ALEX. Within the limited range of the study, the surface-to-volume ratio of the reaction vessel had no significant impact on ignition temperature.