Dense fine-grained aggregates prepared by spark plasma sintering (SPS), an original technique in experimental petrology

We have fabricated dense polyphase mixtures (silicate and oxide minerals, metal, and silicate melt) by Spark Plasma Sintering (SPS), a technique that has only recently been applied to silicates. We describe the SPS method and some of the characteristics of sintered specimens of forsterite, forsterite + MgO, forsterite + metal (Ni or Fe) and forsterite + metal + silicate melt. We show that SPS is a very efficient method to quickly prepare dense (>99 %) polyphase aggregates with homogeneous microstructures (well distributed phases, narrow grain size distributions, polygonal grain boundaries ... ) and small grain sizes with little or no grain growth during sintering. We observe the development of slight Shape Preferred Orientations (SPO), especially for the metal phases, due to the very simple setup we used here. Overall, SPS offers substantial advantages over traditional sintering techniques, making it perfectly suitable for experimental studies in Earth sciences, in particular those involving kinetic processes.