In-Situ Observation on the Agglomeration and Dispersion of Particles at the Interface of High-temperature Melts

Abstract

Understanding the mechanism of particle aggregation and dispersion at a liquid surface is important for the design and fabrication of novel materials. The behaviors of particles with various compositions at the interface of high-temperature melts, including the rapid growth of particles, the linear aggregation or curvilinear motion, and the wetting and separation processes, were observed in situ by high-temperature confocal laser scanning microscopy (HT-CLSM). We experimentally investigated the interaction force on particle pairs as a function of the interparticle distance and the size, composition and shape of particles. The experimental results indicate the attractive force between particle pairs decreases with increasing distance, and it increases as the size of the guest particle increases. The acting length of particles increases in the order of the alumina-magnesia particle (30 µm)< calcium aluminate particle with low CaO contents (80 µm)in situ observation increases in the order of Al₂O₃·35%CaO< Al₂O₃·19%MgO < Al₂O₃·38%MgO < Al₂O₃·15%CaO < Al₂O₃. The complex selective attraction has been observed in the in situ experiments which is attributed to the polydirectional attractive force and anisotropy in the particle morphology. The relationship between the roundness with acceleration rate of particles indicates that the attraction between spherical particles tends to be less than the attraction between irregular particles with edges.