Temperature behavior of exothermic reaction of Al/Ni multilayer powder materials based on cold-rolling and pulverizing method

Abstract

In this paper, the characteristics of self-propagating exothermic reactions of an Al/Ni multilayer powder materials fabricated by a cold-rolling and powdering procedure are reported as initial findings of the first trial on a heat source for various applications with the energy-saving feature. Experimental results showed that, following the reaction of the developed Al/Ni multilayer powder materials in air atmosphere, the maximum temperature increased from approximately 1450 °C to over 1768 °C with increasing number of passes from 20 to 40 in cold-rolling. Furthermore, observations by scanning electron microscopy and crystallographic identification by X-ray diffraction measurements showed that the multilayer structure of powdered Al/Ni after 40 passes of cold-rolling was deformed, became thinner with below sub-micrometer thickness, and almost completely reacted to NiAl intermetallic compounds. It is possible that optimizing cold-rolling conditions enables us to control exothermic heat, which will be useful for heat sources.

Effect of the Particle Size of Al/Ni Multilayer Powder on the Exothermic Characterization

“…Figure 9 shows the dependency of the maximum temperature on the particle size for the quantitative evaluation of the dependency of the duration time of the exothermic reaction on the particle size and the elapsed time from the time the reaction occurred to the time taken to reach a temperature point during heat release (1400, 1200, 1000, and 800 °C) as a function of the particle size was measured, as shown in Figure 11 . Error bar shows 10% of deviation from the average value, which was estimated through N = 2 and more experiments and no lager error was recognized from our previous studies of 40 passes of cold-rolling [ 24 ].…”

“…In a previous study, we fabricated an Al/Ni multilayer powder using the cold-rolling and pulverizing method and discussed its application [ 24 , 25 , 26 , 27 ]. The fabrication of an Al/Ni multilayer powder using these methods overcomes the disadvantages presented by the thin-film technology for the fabrication of an Al/Ni bilayer structure.…”

“…In addition, since the cold-rolling procedure is based on the accumulative roll bonding technique with high reduction, the constructed rolled Al/Ni strip consists of sub-micrometer thick Al/Ni multilayers and cannot achieve the nanoscale thick bilayer fabricated by the thin-film process. Furthermore, we revealed that the maximum temperature of the Al/Ni multilayer powder during the exothermic reaction can be adjusted in the temperature range of 1300–1800 °C by adjusting the conditions of the cold-rolling technique [ 24 , 27 ]. In addition, we also found that the heat energy generated using this method can melt and join aluminum strips [ 25 ] and copper wires [ 26 ].…”

Crystallite size analysis of Al/Ni multilayer powder by synchrotron radiation X-ray diffraction

“…aluminum). [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Usually, Al/Ni multilayer materials are fabricated by alternately stacking Al and Ni layers, which are a few tens of nanometers thick, by physical vapor deposition (PVD). Several papers on the fabrication of Al/Ni multilayer films by the PVD method have been published in the literature.…”

Preparation of Al/Ni Reactive Multilayer Foils and its Application in Thermal Battery

“…The Al/Ni RMFs usually could be produced by electron beam evaporation, vacuum evaporation, mechanical cold rolling, anodizing and magnetron sputtering . Electron beam evaporation technology owns the advantages of simple operation and high efficiency, but it is difficult to achieve stable deposition rate and the process repeatability is poor .…”