MONTE-CARLO SIMULATION OF PARTICLE COAGULATION AND SINTERING

A Monte Carlo simulation has been developed to describe the gas phase coagulation and sintering of nanoclusters. The cluster-cluster aggregation model is modified to include a finite interparticle binding energy. Particle restructuring and densification (sintering) are incorporated into the model by modifying Kadanoff's algorithm for random particle walks on the surface of the cluster. The effect of sintering on aggregate size distribution and fractal dimension has been investigated in simulations of two-dimensional clusters. The binding energy and the relative rates of aggregation and sintering are the primary variables affecting particle structure. In the initial stages, the sintering process results in aggregates which are compact on small length scales. As time progresses and the aggregates become larger, the sintering process slows down and the fractal dimension of the aggregates decreases. The model is able to track the effect of reactor residence time and temperature on the specific surface area and size distribution of aggregates.