Formation of Ba1−Ca TiO3 solid solutions beyond the solubility limit by ‘sputter-anneal’ method

2019 ◽  
Vol 679 ◽  
pp. 178339 ◽  
Author(s):  
Miho Ako ◽  
Takeshi Kogure ◽  
Yumie Kobayashi ◽  
Tôru Kyômen ◽  
Jun-ichi Fujisawa ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Solubility Limit

scholarly journals Thermodynamic Analysis of the Formation of FCC and BCC Solid Solutions of Ti-Based Ternary Alloys by Mechanical Alloying

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 510 ◽  
Author(s):  
Claudio Aguilar ◽  
Carola Martinez ◽  
Karem Tello ◽  
Sergio Palma ◽  
Adeline Delonca ◽  
...  
Keyword(s):  
Free Energy ◽  
Mechanical Alloying ◽  
Gibbs Free Energy ◽  
Thermodynamic Analysis ◽  
Solid Solutions ◽  
Ternary Systems ◽  
Solubility Limit ◽  
Ternary Alloys ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

A thermodynamic analysis of the synthesis of face-centred cubic (fcc) and body-centred cubic (bcc) solid solutions of Ti-based alloys produced by mechanical alloying was performed. Four Ti-based alloys were analysed: (i) Ti-13Ta-3Sn (at.%), (ii) Ti-30Nb-13Ta (at.%), (iii) Ti-20Nb-30Ta (wt. %) and (iv) Ti-33Nb-4Mn (at.%). The milled powders were characterized by X-ray diffraction, and the crystallite size and microstrain were determined using the Rietveld and Williamson–Hall methods. The Gibbs free energy of mixing for the formation of a solid solution of the three ternary systems (Ti-Ta-Sn, Ti-Nb-Ta and Ti-Nb-Mn) was calculated using an extended Miedema’s model, applying the Materials Analysis Applying Thermodynamics (MAAT) software. The values of the activity of each component were determined by MAAT. It was found that increasing the density of crystalline defects, such as dislocations and crystallite boundaries, changed the solubility limit in these ternary systems. Therefore, at longer milling times, the Gibbs free energy increases, so there is a driving force to form solid solutions from elemental powders. Finally, there is agreement between experimental and thermodynamic data confirming the formation of solid solutions.

Hydrothermal Synthesis and Properties of Ce1−xMxO2-δ(M = La, Bi, Sm, Pr, Tb) Solid Solutions

1998 ◽  
Vol 548 ◽  
Author(s):  
M. Greenblatt ◽  
P. Shuk ◽  
W. Huang ◽  
S. Dikmen ◽  
M. Croft
Keyword(s):  
Solid Solutions ◽  
Ultrafine Particles ◽  
Electronic Conductivity ◽  
Solubility Limit ◽  
Hydrothermal Conditions ◽  
Oxide Systems ◽  
Oxide Ion Conductivity ◽  
Maximum Conductivity ◽  
Crystallite Dimension ◽  
20 Nm

ABSTRACTA systematic study of hydrothermally prepared Ce1−x,MxO2−δ, (M= Sm, Bi, Pr, Tb; x= 0-0.30) solid solutions, promising materials for application in solid oxide fuel cells and oxygen membranes is presented. Ultrafine particles of uniform crystallite dimension, ∼ 20 nm can be formed in 30 min. under hydrothermal conditions (260°C, 10 MPa). The small particle size (20-50 nm) of the hydrothermally prepared materials allows sintering of the samples into highly dense ceramics at 900-1350°C, significantly lower temperatures than 1600-1650°C required for samples prepared by solid state techniques. The solubility limit of Bi2O3, in CeO2, was determined to be around 20 mol. %. The maximum conductivity, σ600°C ∼ 4.4 × 10−3 S/cm with Ea = 1.01 eV, and σ600°C = 5.7 × 10−3 S/cm with Ea ≈ 0.9 eV was found at x= 0.20 and x= 0.17 for Bi and Sm, respectively. In the Ce-Pr/Tb oxide systems, in addition to the high oxide ion conductivity, electronic conductivity occurs through the hopping of small polarons by a thermally activated mechanism (electron hopping from the Pr3+/Tb3+ to a neighboring Pr4+/Tb4+ ion).

scholarly journals Formation of Solid Solutions and Physicochemical Properties of the High-Entropy Ln1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ (Ln = La, Pr, Nd, Sm or Gd) Perovskites

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5264
Author(s):  
Juliusz Dąbrowa ◽  
Klaudia Zielińska ◽  
Anna Stępień ◽  
Marek Zajusz ◽  
Margarita Nowakowska ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Physicochemical Properties ◽  
Solid Solutions ◽  
Pechini Method ◽  
Solubility Limit ◽  
Secondary Phases ◽  
Chemical Expansion ◽  
High Entropy ◽  
Total Electrical Conductivity ◽  
Rhombohedral Crystal Structure

Phase composition, crystal structure, and selected physicochemical properties of the high entropy Ln(Co,Cr,Fe,Mn,Ni)O3−δ (Ln = La, Pr, Gd, Nd, Sm) perovskites, as well as the possibility of Sr doping in Ln1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ series, are reported is this work. With the use of the Pechini method, all undoped compositions are successfully synthesized. The samples exhibit distorted, orthorhombic or rhombohedral crystal structure, and a linear correlation is observed between the ionic radius of Ln and the value of the quasi-cubic perovskite lattice constant. The oxides show moderate thermal expansion, with a lack of visible contribution from the chemical expansion effect. Temperature-dependent values of the total electrical conductivity are reported, and the observed behavior appears distinctive from that of non-high entropy transition metal-based perovskites, beyond the expectations based on the rule-of-mixtures. In terms of formation of solid solutions in Sr-doped Ln1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ materials, the results indicate a strong influence of the Ln radius, and while for La-based series the Sr solubility limit is at the level of xmax = 0.3, for the smaller Pr it is equal to just 0.1. In the case of Nd-, Sm- and Gd-based materials, even for the xSr = 0.1, the formation of secondary phases is observed on the SEM + EDS images.

Investigation of AgI-Based Solid Solutions with Ag2CO3

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 54
Author(s):  
Kento Uchida ◽  
Yuta Matsushima
Keyword(s):  
Thermal Analysis ◽  
Electrical Conductivity ◽  
Differential Thermal Analysis ◽  
Solid Solutions ◽  
Conductivity Measurement ◽  
Solubility Limit ◽  
Reaction Products ◽  
Electrical Conductivity Measurement ◽  
Rich Region ◽  
Silver Carbonate

The formation phenomena of silver carbonate (Ag2CO3)–silver iodide (AgI) solid solutions were investigated by X-ray diffraction, thermogravimetry-differential thermal analysis, and electrical conductivity measurement. Results revealed that AgI and Ag2CO3 reacted with each other when mixed at room temperature. The reaction products were classified into three types: (1) AgI-based solid solutions in the AgI-rich region for x = 10% or less in x Ag2CO3–(1 − x) AgI; (2) Ag2CO3-based solid solutions in the Ag2CO3-rich region for x = 60% or more; and (3) silver carbonate iodides in the intermediate range for x between 10% and 60%. For the AgI-based solid solutions, the incorporation of Ag2CO3 into the AgI lattice expanded the unit cell and enhanced electrical conductivity. The solubility limit of Ag2CO3 into the AgI lattice estimated from the differential thermal analysis was x ≈ 5%.

Sign in / Sign up

Export Citation Format

Share Document