Fig. 4
High-speed microscopy images capturing the reactive sintering process in-operando. a Series of reactive sintering and ignition snapshots of a group of particles (labeled is frame sequence, 55.55 µs per frame, scale bar: 100 µm) and b its corresponding schematic cartoon. Note: The marked arrows are propagating direction. c The corresponding scanning electron microscopy (SEM) image of the sintered Al2O3 particles coated with Cu nanoparticles, as evident by the energy-dispersive spectrometry (EDS) results in Fig. S5
