Direct Imaging and Simulation of the Interface Reaction of Metal/Metal Oxide Nanoparticle Laminates

Abstract

One of the difficulties in understanding how powder composites of reactive fuel/oxidizer systems behave is the lack of control of the mixing length. In this study, we have prepared Al/CuO particle laminates using a direct writing approach. With as little as 10 wt % polymers, we were able to obtain free-standing microscale particle-based laminates. Using these composites, we were able to image the cross section of the laminates to directly probe the interface reaction with highspeed microscopic imaging and pyrometry. We show quantitatively how the burn rate can be altered by changing the layer thicknesses of the printed laminates and under high-speed microscopy imaging asymmetry heat transfer resulting in fingering in the temperature profiles in the reaction front. Numerical simulations of the heat and mass transport processes are able to reproduce the finger-structured reaction fronts. We find that for Al/CuO particle-based laminates, the lateral O 2 diffusion rate from the CuO layer to the Al layer appears to be rate-limiting. The finger-like profiles appear due to the combined effects from the faster propagation of the interfacial reaction over the bulk, and the thermal diffusivity differences between the Al/CuO layers. Interestingly we see no evidence of layer intermixing even on postcombustion inspection. These results are to our knowledge the first imaging of interface reactions between particle composites and provide a valuable testbed for probing mechanisms and validating models.

Generalized Energy-Conserving Dissipative Particle Dynamics with Mass Transfer. Part 2: Applications and Demonstrations

“…Adaptation of the GenDPDE-M method to isothermal conditions is underway and will be published elsewhere. Still other adaptions include the extension of GenDPDE-M to include chemical reactions, allowing for the simulation of mass transfer between particles coupled to chemical reactions, for example, diffusion-governed reactive response of energetic materials, , as well as a general coupling between mass and energy transport, which is the essential ingredient underlying the Ludwig-Soret phenomenon.…”

UV-Light-Driven Photocatalytic Dye Degradation and Antibacterial Potentials of Biosynthesized SiO2 Nanoparticles

“…Metal oxide nanoparticles can be synthesized via different methods like green synthesis, sol-gel, co-precipitation, chemical/physical vapor deposition and hydrothermal methods [10][11][12][13][14]. Green synthesis is one of the best synthesis processes due to its lower toxicity, ease of use, low energy consumption and the fact that no secondary toxic compounds are composed in the synthesis time [14][15][16][17].…”

Generalized Energy-Conserving Dissipative Particle Dynamics with Mass Transfer. Part 1: Theoretical Foundation and Algorithm

“…While it may be reasonable under some conditions to neglect mass transfer between particles (e.g., reacting systems with large Damkoḧler numbers), even in those circumstances, as the CG model resolution increases (i.e., fewer DoF are coarse grained into the model), this assumption becomes nebulous. Some specific potential applications include diffusion-governed mixing of reactive laminates 38 and the reactive response of shocked materials. 10 The development of a particle-based CG method that can simulate diffusion-governed behavior would address this computational gap in microscale modeling and simulation.…”