Papers by Keyword: Fluorite Structure

Abstract: The purpose of the work is influence investigation of modifying Nd₅Mo₃O_16+δ oxygen-conducting fluorite-related compound by lead at the crystal structure and conductivity. The substitution of lead for neodymium was studied by XRD (with structure refinement), scanning electron microscopy, FTIR-spectroscopy and conductivity measurements. The compositions Nd_5-xPb_xMo₃O_16+δ (x = 0 – 1.6) were obtained by a solid state reaction from the oxides. It was determined that single-phase solid solution Nd_5-xPb_xMo₃O_16+δ is formed up to x ≈ 0.82. The Rietveld structure refinement shows that lead is statistically located in the Ln1 and Ln2 positions. The introduction of lead does not significantly affect the nature and values of conductivity.

Abstract: Substitution rare-earth elements for cadmium in the monoclinic compounds Ln₂MoO₆ (Ln – Gd, Ho) leads to the formation of fluorite-related cubic structure. Series Ln_2xCd_xMoO_6x/2 was investigated by XRD (with structure refinement), scanning electron microscopy, FTIR-spectroscopy and conductivity measurements.

Abstract: Thin films of mixtures of molybdenum silicate (MoSi2) and silicon (Si) (MoSiX, where the Mo to Si molar ratio = 1:X) were deposited on silicon nitride (Si3N4) polycrystalline substrates by radio-frequency magnetron sputtering using a target made of a mixture of MoSi2 and Si powders. The crystal structure of MoSiX thin films deposited on the Si3N4 substrate consisted of a mixture of a hexagonal phase and an unknown phase when X > 2.05. A thin film consisting almost entirely of the unknown phase could be deposited when X = 2.1−2.15. Molybdenum silicate can exist in the forms Mo3Si, Mo5Si3, or MoSi2, but to date there has been no report of molybdenum silicate having a Si to Mo molar composition ratio of larger than 2. It was found that the surfaces of thin films of the hexagonal phase or the unknown phase were readily oxidized, whereas the surfaces of thin films of a mixture of the hexagonal phase and the unknown phase exhibit excellent oxidation resistance in air at temperatures up to 700 °C.