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Nanocrystalline EuCrO3 particles (∼25 nm) have been prepared by pre-milling a 1 : 1 molar mixture of Eu2O3 and Cr2O3 for 60 h followed by sintering at 700 °C (12 h). This temperature is ∼500–600 °C lower than those at which the material, in bulk form, is conventionally prepared. Rietveld analysis of the x-ray powder diffraction pattern of the EuCrO3 nanoparticles favours a structural model involving a slight degree of cationic exchange where ∼11% of the Eu3+ and Cr3+ ions exchange their normal dodecahedral A- and octahedral B-sites, respectively, in the perovskite-related structure. This cationic site exchange, which is unusual in a perovskite structure, has been well supported by the corresponding room-temperature 151Eu Mössbauer spectrum of the nanoparticles that in addition to displaying a distribution in the principal component of the EFG tensor (V zz ) at the usual A-sites of the 151Eu nuclei, also revealed the presence of a subcomponent with ∼11% area fraction and a considerably increased |V zz | value that was associated with Eu3+ ions at octahedral B-sites. X-ray photoelectron and Auger electron spectroscopic techniques reveal a complex surface structure where extremely thin layers of un-reacted Eu2O3 and Cr2O3 cover most of the EuCrO3 nanoparticles' surfaces together with some traces of elemental Cr. The binding energies associated with Eu3+ 3d5/2, Eu3+ 4d3/2, Cr3+ 2p3/2 and O2− 1s core-level electrons in EuCrO3 are estimated from the x-ray photoelectron data for the first time.

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This paper introduces new soil stabilisers for reducing the swelling potential of expansive soils. In this study three different polymers (furan, poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVA)) were utilised as soil stabilisers. For evaluating the effect of these polymers on swelling potential and microfabric of expansive soils, three soil samples of high plasticity index were selected. First the engineering, chemical and mineralogical characteristics of the untreated soils were determined, and three different pairs of dry density and water content (dry of optimum, optimum and wet of optimum) were chosen, from standard Proctor compaction curve. Treated soil specimens were prepared at 3%, 5% and 10% of furan content and 1%, 3% and 5% of polymethyl methacrylate and polyvinyl acetate content. The addition of polymethyl methacrylate and polyvinyl acetate can also diminish the swelling potential of soil specimens, but to a lesser degree. The addition of additives produced aggregations and clay-granular matrices within the fabric, which reduced the swelling potential of the soil samples.

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