scholarly journals Copper-doped lanthanum manganite La0.65Ce0.05Sr0.3Mn1−xCuxO3 influence on structural, magnetic and magnetocaloric effects

RSC Advances ◽  
2018 ◽  
Vol 8 (13) ◽  
pp. 7186-7195 ◽  
Author(s):  
M. Chebaane ◽  
R. Bellouz ◽  
Ma. Oumezzine ◽  
E. K. Hlil ◽  
A. Fouzri
Keyword(s):  
Pechini Method ◽  
Sol Gel ◽  
Lanthanum Manganite ◽  
Bulk Nanocrystalline

Bulk nanocrystalline samples of La0.65Ce0.05Sr0.3Mn1−xCuxO3 (0 ≤ x ≤ 0.15) manganites are prepared by the sol–gel based Pechini method.

scholarly journals Pr3+ doping at the A-site of La0.67Ba0.33MnO3 nanocrystalline material: assessment of the relationship between structural and physical properties and Bean–Rodbell model simulation of disorder effects

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25627-25637 ◽  
Author(s):  
Ma. Oumezzine ◽  
Herbet Bezerra Sales ◽  
Ahmed Selmi ◽  
E. K. Hlil
Keyword(s):  
Physical Properties ◽  
Carrier Concentration ◽  
Nanocrystalline Material ◽  
Model Simulation ◽  
Pechini Method ◽  
Sol Gel ◽  
Disorder Effects ◽  
Bulk Nanocrystalline ◽  
A Site ◽  
The Relationship

Bulk nanocrystalline samples of (La1−xPrx)0.67Ba0.33MnO3 (0.075 ≤ x ≤ 0.30) manganites with a fixed carrier concentration are prepared by the sol–gel based Pechini method.

Pressure assisted sintering of Al2O3–Y2O3 glass microspheres: sintering conditions, grain size, and mechanical properties of sintered ceramics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Anna Prnová ◽  
Jana Valúchová ◽  
Monika Michálková ◽  
Beáta Pecušová ◽  
Milan Parchovianský ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Hot Pressing ◽  
Pechini Method ◽  
Sol Gel ◽  
Applied Pressure ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Glass Microspheres ◽  
Amorphous Powders

Abstract Glass microspheres with yttria-alumina eutectic composition (76.8 mol % Al2O3 and 23.2 mol % Y2O3) were prepared by sol-gel Pechini method and flame synthesis with or without subsequent milling. Prepared amorphous powders were studied by X-ray powder diffraction (XRD), particle size analysis (PSA), scanning electron microscopy (SEM) and differential thermal analysis (DTA). Hot pressing (HP), rapid hot pressing (RHP) and spark plasma sintering (SPS) were used to sinter amorphous precursor powders at 1600 °C without holding time (0 min). The preparation process including milling step resulted in amorphous powders with narrower particle size distribution and smaller particle size. All applied pressure assisted sintering techniques resulted in dense bulk samples with fine grained microstructure consisting of irregular α-Al2O3 and Y3Al5O12 (YAG) grains. Milling was beneficial in terms of final microstructure refinement and mechanical properties of sintered materials. A material with the Vickers hardness of HV = (17.1 ± 0.3) GPa and indentation fracture resistance of (4.2 ± 0.2) MPa.m1/2 was prepared from the powder milled for 12 h.

Sol–gel based Pechini method synthesis and characterization of Sm1−xCaxFeO3 perovskite 0.1≤x≤0.5

2012 ◽  
Vol 229 ◽  
pp. 290-293 ◽  
Author(s):  
A.M. Huízar-Félix ◽  
T. Hernández ◽  
S. de la Parra ◽  
J. Ibarra ◽  
B. Kharisov
Keyword(s):  
Pechini Method ◽  
Sol Gel ◽  
Synthesis And Characterization

Synthesis of Pure Dicalcium Silicate Powder by the Pechini Method and Characterization of Hydrated Cement

2014 ◽  
Vol 787 ◽  
pp. 387-394 ◽  
Author(s):  
Yan Ni Tan ◽  
Yong Liu ◽  
Zhang Qing ◽  
Gurpreet Birdi ◽  
Liam M. Grover
Keyword(s):  
Solid State ◽  
Mass Loss ◽  
Solid State Reaction ◽  
Pechini Method ◽  
Sol Gel ◽  
Dicalcium Silicate ◽  
Hydrated Cement ◽  
Gel Method ◽  
Sol Gel Method

Calcium silicate (CS) is a main component of Portland cement and is responsible for the strength development. Recent research has shown that dicalcium silicate cement (CSC) is bioactive and is a potential candidate for bone replacement. Traditionally, dicalcium silicate powder is synthesized by a solid state reaction or a sol-gel method. The solid-state reaction, however, usually needs a higher temperature and a longer calcination time. Furthermore, the dicalcium silicate powder made by the sol-gel method is not pure, and contains a significant quantity of CaO which is harmful to the strength and biological properties of the CSC. The Pechini technique is an alternative, low temperature polymeric precursor route for synthesis of high purity powders. In this study, purer CS powder was synthesized via the Pechini method by calcination at 800°C for 3h. DSC-TGA, XRD, SEM were used for characterization of CS powder and the hydrated cement. The DSC-TGA curves showed that the main exothermic peak was at 479°C and the total mass loss was 79.2%. The XRD patterns of CSC after hydration for 7, 14, and 35 days illustrated that dicalcium silicate hydrate (Ca1.5SiO3.5·xH2O, C-S-H) was formed in the hardened CS paste. The XRD peaks on the diffraction pattern of the C-S-H of the day 35 sample were of greater intensity than those at day 7 and day 14. This demonstrates that the hydration speed was slow and complete hydration could take more than one month. Flake-like crystals were observed on scanning electron micrographs following hardening. The degradation study result showed that there was no mass loss of CSC after the samples were soaked into phosphate buffered saline (PBS) for 40 days. The silicon assay revealed that orthosilicic acid could be released from CSC after the samples were soaked in simulated body fluid (SBF). Silicon is known to be critical to skeletal mineralization. The existence of silicon may stimulate the proliferation of bone and activate cells to produce bone. Investigation of cell attachment confirmed that the MC-3T3 cells attached well to the surfaces of CSC after seeding.

A microwave-assisted sol–gel Pechini method for the synthesis of BaCe0.65Zr0.20Y0.15O3−δ powders

2010 ◽  
Vol 45 (9) ◽  
pp. 1171-1176 ◽  
Author(s):  
S. Barison ◽  
M. Fabrizio ◽  
S. Fasolin ◽  
F. Montagner ◽  
C. Mortalò
Keyword(s):  
Pechini Method ◽  
Sol Gel ◽  
Microwave Assisted

EFFECT OF LANTHANUM MANGANITE MODIFICATION BY CALCIUM AND/OR FLUORINE ON THE BONDING STRENGTH, MOBILITY AND REACTIVITY OF THE LATTICE AND SURFACE OXYGEN

2002 ◽  
Vol 751 ◽  
Author(s):  
V. A. Sadykov ◽  
T. G. Kuznetsova ◽  
A. V. Simakov ◽  
V. A. Rogov ◽  
V. I. Zaikovskii ◽  
...  
Keyword(s):  
Surface Composition ◽  
Pechini Method ◽  
Lanthanum Manganite ◽  
Surface Oxygen ◽  
Weakly Bound ◽  
Pulse Flow ◽  
Bulk Oxygen ◽  
Oxygen Excess ◽  
Reasonable Description ◽  
Weakly Bound Oxygen

ABSTRACTCa and/or F-modified samples of LaMnO3 have been prepared by the Pechini method. The bulk structure of samples was characterized by TEM, EXAFS and XRD, while the surface composition was studied by SIMS. Thermal analysis, O2 TPD, H2 TPR and isothermal pulse/flow samples reduction by CO were applied to characterize the accessible surface/bulk oxygen mobility and reactivity. A reasonable description of the experimental energetic spectrum of the surface oxygen for various types of regular and defect surface sites on the perovskite faces was achieved by using semiempirical Interacting Bonds Method in the slab approximation with a due regard for the surface face termination and relaxation. Fluorine was found to decrease the surface coverage by reactive weakly bound oxygen forms while increasing the bulk oxygen excess and mobility. Calcium generated reactive weakly bound oxygen forms while decreasing the oxygen excess in the lattice and converting the regular M-O oxygen forms into the bridging ones through migration to the surface.

Preparation and Properties of Yttrium Doped Barium Cerate (BaCe1-xYxO3-δ)

2015 ◽  
Vol 1098 ◽  
pp. 69-74
Author(s):  
Eduardo R. Magdaluyo ◽  
Jomyr E. Gapasin
Keyword(s):  
Ceramic Material ◽  
Proton Conductivity ◽  
Pechini Method ◽  
Sol Gel ◽  
Secondary Phase ◽  
Processing Parameters ◽  
Homogeneous Distribution ◽  
Barium Cerate ◽  
X Ray Diffraction ◽  
Doped Barium Cerate

Yttrium doped barium cerate is considered a promising electrolyte material for solid oxide fuel cell applications due to its excellent proton conductivity. The proton conductivity characteristics of the ceramic material can be influenced by the different synthesis processing parameters. This study aimed to obtain yttrium doped barium cerate BaCe1-xYxO3-δ (x = 0.15, 0.20) using a sol-gel modified Pechini method. The phase formation and surface morphology of the yttrium doped barium cerate were investigated using x-ray diffraction and scanning electron microscopy. The thermal decomposition of the calcined ceramic material was examined using thermogravimetric analysis. Diffraction analysis confirmed the formation of perovskite crystalline structure with the presence of secondary phase yttrium doped ceria. Larger grain size with homogeneous distribution and coalescence was observed in the sintered BaCe0.80Y0.20O3-δ.

NiO/YSZ Composites for SOFC: Synthesis and Characterization

2006 ◽  
Author(s):  
R. F. Martins ◽  
M. C. Brant ◽  
R. Z. Domingues ◽  
T. Matencio
Keyword(s):  
Sol Gel ◽  
World Market ◽  
Physical Mixture ◽  
Solid Oxide ◽  
Yttria Stabilized Zirconia ◽  
Lanthanum Manganite ◽  
Stabilized Zirconia ◽  
Chemical Methods ◽  
Grain Sizes

Solid oxide fuel cell (SOFC) works at high temperature and is normally used in stationary devices which are of wide interest in the world market. The most currently SOFC developers utilize yttria-stabilized zirconia (YSZ) as electrolyte, strontium-doped lanthanum manganite (LSM) as cathode and a Ni/YSZ cermet obtained from NiO/YSZ in situ reduction as anode. The electrode performance is directly influenced by powder grain sizes, homogeneity, purity, and amount of Ni. Although physical mixture is a simpler procedure it hardly gives homogeneous materials as suitable to SOFC applications. Alternative chemical methods are sol-gel, impregnation and those derived from Pechini route. The present work compares thermal stability and hydrogen reducibility of NiO/YSZ composites prepared by impregnation (I), Pechini (P) and physical mixture (PM) procedures.

scholarly journals Preparation of La0.7Ca0.3−xSrxMnO3 Manganites by Four Synthesis Methods and Their Influence on the Magnetic Properties and Relative Cooling Power

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 309 ◽  
Author(s):  
María Botello-Zubiate ◽  
María Grijalva-Castillo ◽  
Daniel Soto-Parra ◽  
Renee Sáenz-Hernández ◽  
Carlos Santillán-Rodríguez ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Solid State ◽  
Solid State Reaction ◽  
Pechini Method ◽  
Sol Gel ◽  
Relative Cooling Power ◽  
Cooling Power ◽  
Synthesis Methods ◽  
Consolidation Process

Manganites of the family La0.7Ca0.3−xSrxMnO3 were fabricated by four preparation methods: (a) the microwave-assisted sol-gel Pechini method; (b) sol-gel Pechini chemical synthesis; (c) solid-state reaction with a planetary mill; and (d) solid-state reaction with an attritor mill, in order to study the effect of the preparation route used on its magnetocaloric and magnetic properties. In addition, the manganites manufactured by the Pechini sol-gel method were compacted using Spark Plasma Sintering (SPS) to determine how the consolidation process influences its magnetocaloric properties. The Curie temperatures of manganites prepared by the different methods were determined in ~295 K, with the exception of those prepared by a solid-state reaction with an attritor mill which was 301 K, so there is no correlation between the particle size and the Curie temperature. All samples gave a positive slope in the Arrot plots, which implies that the samples underwent a second order Ferromagnetic (FM)–Paramagnetic (PM) phase transition. Pechini sol-gel manganite presents higher values of Relative Cooling Power (RCP) than the solid-state reaction manganite, because its entropy change curves are smaller, but wider, associated to the particle size obtained by the preparation method. The SPS technique proved to be easier and faster in producing consolidated solids for applications in active magnetic regenerative refrigeration compared with other compaction methods.

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