Theoretical and Experimental Investigations on Sintering Kinetics of SilicaNanoparticles

摘要

The sintering kinetics of single silica nanoparticle contacts in the gas phase is investigatedexperimentally and theoretically. Experiments are conducted in a high-temperature short-time flowreactor allowing for precise control of temperature and residence time. Sintering experiments havebeen conducted for temperatures up to 1600 "C and residence times down to 5 ms. Results showsignificantly shorter sintering times than predicted by macroscopic sintering models. For vitreousmaterials such as silica the predominant sintering mechanism is supposed to be viscous flow.Therefore, three dimensional simulations of the sintering process have been conducted by solvingthe free surface viscous flow process using a volume-of-fluid (VOF) method. Additionally, van derWaals interactions have been considered as momentum source. The results suggest that molecularvan der Waals interactions have great influence on the sintering kinetics of nanoparticles which isinsufficiently described by macroscopic models.