Paola Riani

Thermodynamic measurements and assessment of the Al–Sc system

Abstract A study of the binary Al-Sc phase diagram has been performed by means of thermodynamic calculations and experimental measurements. The enthalpy of formation of all intermetallic compounds has been determined and a cursory examination of the phase equilibria carried out, for compositions greater than 40 at% Sc. Two new invariant reactions have been identified in the Sc-rich part of the diagram: L ↔ (βSc)+Sc2Al at 1185°C and (βSc) ↔ Sc2Al+(αSc) at 970°C. A coherent set of Gibbs energy expressions for all the phases in the system has been generated by a least square optimisation procedure using all the experimental data available. The overall agreement is satisfactory but some uncertainties still persist, especially concerning the ScAl phase, owing to experimental difficulties.

The isothermal section at 400 °C of the Ce-Cu-Sn ternary system

Ternary Ce-Cu-Sn alloys have been studied by X-ray diffraction (XRD), optical and scanning electron microscopy and electron probe microanalysis (EPMA). Phase equilibria have been established in the isothermal section at 400 °C: 4 ternary compounds have been confirmed, 4 new compounds determined and 34 tie triangles identified.

Yb–Cu–Sn system: the isothermal section at 400°C

Abstract Phase equilibria in the ternary system Yb–Cu–Sn have been studied by X-ray powder diffraction analysis, optical and scanning electron microscopy and electron probe microanalysis. The isothermal section has been analysed at 400°C: 10 ternary compounds have been confirmed or determined and the corresponding tie-triangles defined. The ternary compounds are YbCu4.4Sn0.6, Yb3Cu13Cu4, Yb14Cu60Sn26, YbCu9Sn4, Yb30Cu39Sn31, YbCuSn, Yb5CuSn3, Yb23Cu42Sn35, Yb3Cu4Sn4, Yb36Cu18Sn46.

Functionalization of Fe3O4 NPs by Silanization: Use of Amine (APTES) and Thiol (MPTMS) Silanes and Their Physical Characterization

In this paper the results concerning the synthesis of magnetite (Fe3O4) nanoparticles (NPs), their functionalization using silane derivatives, such as (3-Aminopropyl)triethoxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane (MPTMS), and their exhaustive morphological and physical characterization by field emission scanning electron microscopy (FE-SEM) with energy dispersion X-ray spectrometer (EDX) analysis, AC magnetic susceptibility, UV-VIS and IR spectroscopy, and thermogravimetric (TGA) analyses are reported. Two different paths were adopted to achieve the desired functionalization: (1) the direct reaction between the functionalized organo-silane molecule and the surface of the magnetite nanoparticle; and (2) the use of an intermediate silica coating. Finally, the occurrence of both the functionalization with amino and thiol groups has been demonstrated by the reaction with ninhydrin and the capture of Au NPs, respectively.

Contribution to the investigation of ternary Pr–Cu–Sn alloys

Abstract With regard to the work in progress on the ternary R–Cu–Sn alloys formed by the rare earths, the data obtained in a partial revision of the Pr–Cu–Sn system are reported. The isothermal section at 400°C has been studied in the composition range: PrCu 5 –Pr–Pr 5 Sn 3 –PrCuSn. The general characteristics of the systems formed by the light R are compared and discussed.

The isothermal section at 400°C of the Yb–Ag–Sn ternary system

Abstract The Yb–Ag–Sn isothermal section at 400°C has been investigated by means of X-ray diffraction, optical and scanning electron microscopy and electron probe microanalysis. The following ternary compounds have been identified or confirmed: τ1∼Yb25Ag50Sn25, τ2∼Yb50Ag25Sn25 to Yb46Ag24Sn30, τ3 ∼Yb19Ag50Sn31, τ4∼YbAgSn. Moreover a phase τx∼Yb50Ag35Sn15, not definitively confirmed, has been observed in a few samples. A subdivision of the composition triangle into tie-triangles has been obtained. The general characteristics of the section have been discussed in comparison with those of other R–Ag–Sn systems.

A contribution to the crystallochemistry of ternary 1:1:1 and 1:1:2 rare earth intermetallic phases with Pb and Pd

Abstract The ternary alloys of the rare earths with lead and palladium were studied for the stoichiometric ratios 1:1:1 and 1:1:2 with respect to the structure of these alloys and their existence field. RPbPd (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb) compounds have a hexagonal structure, hP9 Fe 2 P type, while RPbPd 2 (R = Pr, Sm, Gd, Tb, Dy, Ho, Er, Yb) alloys have the cubic AlCu 2 Mn-type structure (cF16, BiF 3 superstructure).

The isothermal section at 400 °C of the phase diagram CeCuSn in the region between CeCu2Ce3Sn7Ce

Abstract The isothermal section at 400 °C of the phase diagram CeCuSn in the region between CeCu 2 Ce 3 Sn 7 -Ce was investigated by X-ray diffraction, optical microscopy and electron probe microanalysis. In this region of the isothermal section, five ternary compounds have been confirmed or determined and 14 tie triangles identified.

NdCuSn system: identification of ternary phases and partial determination of the isothermal section at 400°C

Abstract The partial isothermal section at 400°C of the phase diagram NdCuSn was investigated by X-ray diffraction, optical and scanning electron microscopy and electron probe microanalysis. In the studied region of the isothermal section, nine ternary compounds have been confirmed or determined and 14 tie-triangles identified.

Preparation and characterization of ternary NdPrSb alloys

Ternary Nd-Pr-Sb alloys were studied using X-ray powder diffraction and optical and electron microscopy. (Nd, Pr) 2 Sb (tI12-La 2 Sb type), (Nd, Pr) 4 Sb 3 (cI28-anti-Th 3 P 4 type), (Nd, Pr)Sb (cF8-NaCl type) and (Nd, Pr)Sb 2 (oC24-SmSb 2 type) show complete solubility between Nd and Pr. The variation of the lattice parameters as a function of the Nd to Pr ratio was determined. In addition, the alloy Nd 0.475 Pr 0.475 Sb 0.05 was investigated by differential thermal analysis (DTA). The results obtained confirm a previous thermodynamic prediction of the Nd-Pr-Sb phase equilibria