Logo Logo

Pereira, Luiz ORCID: 0000-0001-9555-0352; Vasseur, Jérémie; Wadsworth, Fabian B.; Trixler, Frank; Dingwell, Donald B. ORCID: 0000-0003-3683-7083 (2022): Interparticle and Brownian forces controlling particle aggregation and rheology of silicate melts containing platinum-group element particles. Scientific Reports, 12: 9226. ISSN 2045-2322

[thumbnail of s41598-022-12948-1.pdf] Published Article

The publication is available under the license Creative Commons Attribution.

Download (2MB)


We study the rheology of silicate melts containing platinum-group element (PGE) particles. They exhibit a shear-thinning behaviour, an intense aggregation tendency, and an anomalously high apparent viscosity in the low shear rate limit, even at very low particle volume fraction. Using a compilation of published experimental data, we analyse these effects in three steps. Firstly, we observe that the viscosities of these suspensions are much higher than those of natural silicate crystal-bearing melts for low shear rate regimes. Secondly, we demonstrate that the viscosities at low shear rate limit cannot be estimated by classical rheological models but rather may be understood as the result of particle aggregation, trapping dead fluid, and thereby increasing the effective particle volume fraction. Finally, we scale the critical shear rates for shear-thinning using a Peclet number analysis—invoking a competition between random thermal particle motion and hydrodynamic shearing motion—and, using an empirical extension, we additionally account for the particle–particle interaction energetics. We propose a framework in which the rheology of this family of particle-bearing melts can be predicted, and demonstrate that at low Peclet numbers, PGE-bearing particle aggregation is driven by interparticle forces and Brownian motion.

View Item
View Item