Formation and phase evolution of calcium phosphates modulated by ion exchange ionomer Nafion

CrystEngComm ◽  
2020 ◽  
Vol 22 (47) ◽  
pp. 8243-8250
Author(s):  
Shuquan Sun ◽  
Qixuan Chen ◽  
Qijun Song
Keyword(s):  
Phase Transition ◽  
Ion Exchange ◽  
Calcium Phosphates ◽  
Phase Evolution

The phase transition of calcium phosphates regulated by Nafion with the inherent acidity and ion exchange features.

Phase Transition of Cl--Intercalated Hydrotalcite-like Compound during Ion Exchange with Phosphates

Langmuir ◽  
1994 ◽  
Vol 10 (2) ◽  
pp. 407-411 ◽  
Author(s):  
Akira Ookubo ◽  
Kenta Ooi ◽  
Fumio Tani ◽  
Hiromu Hayashi
Keyword(s):  
Phase Transition ◽  
Ion Exchange

scholarly journals Investigation of structural phase evolution and dielectric response of Co-doped BaTiO3

2018 ◽  
Vol 08 (04) ◽  
pp. 1850024 ◽  
Author(s):  
Amantulla Mansuri ◽  
Ilyas Noor Bhatti ◽  
Imtiaz Noor Bhatti ◽  
Ashutosh Mishra
Keyword(s):  
Phase Transition ◽  
Structural Study ◽  
Structural Phase ◽  
Structural Evolution ◽  
Phase Evolution ◽  
Dielectric Measurement ◽  
Cubic Phase ◽  
Tangent Loss ◽  
Ionic Radii ◽  
Co Doping

In the present study, we have synthesized polycrystalline samples of BaTi[Formula: see text]CoxO3 (BTCO) ([Formula: see text], 0.01, 0.03, 0.05, 0.07 and 0.10) with standard solid state reaction technique. The obtained samples are characterized by X-ray diffraction (XRD) and Raman spectroscopy for structural study. The detailed structural analysis has been performed by Rietveld refinement using Fullprof program. We observed an increase in lattice parameters, which results due to substitution of Co[Formula: see text] with large ionic radii (0.9[Formula: see text]Å) for smaller ionic radii (0.6[Formula: see text]Å) Ti[Formula: see text]. Moreover, peak at 45.5∘ shifts to 45∘ on Co doping, which is due to structure phase transition from tetragonal to cubic. Raman study infers that the intensity of characteristic peaks decreases and line width increases with Co doping. The bands linked with the tetragonal structure (305[Formula: see text]cm[Formula: see text]) decreased due to the tetragonal-to-cubic phase transition with Co doping. Our structural study reveals the expansion of BTCO unit cell and tetragonal-to-cubic phase transformation takes place. The results from different characterization techniques are conclusive and show structural evolution with Co doping. The samples are further characterized by dielectric spectroscopy, dielectric measurement reveals the increase of dielectric constant and transition [Formula: see text]C is observed for Barium titanate (BaTiO3), whereas transition disappears with Co doping. Both temperature and frequency-dependent tangent loss is also studied.

Pressure Induced AF - F - AF Magnetic Phase Transformations in Pd Substituted FeRh Compound

2012 ◽  
Vol 190 ◽  
pp. 299-302 ◽  
Author(s):  
A.M. Chirkova ◽  
A.S. Volegov ◽  
D.S. Neznakhin ◽  
E.A. Stepanova ◽  
N.V. Baranov
Keyword(s):  
Phase Transition ◽  
Critical Temperature ◽  
Hydrostatic Pressure ◽  
Curie Temperature ◽  
Phase Transformations ◽  
Magnetic Phase ◽  
Ambient Pressure ◽  
Phase Evolution

At ambient pressure, the Fe0.49(Rh1-xPdx)0.51 alloys with the Pd concentration within 0 < x < 0.12 exhibit an antiferromagnetic (AF) state below the critical temperature Tt, while above x = 0.12 the alloys have a ferromagnetic (F) order up to the Curie temperature TC 650 K. The temperature and field dependences of the magnetization in the alloys with x = 0.08; 0.13 were investigated under hydrostatic pressure up to 10 kbar. The application of pressure of about 8.5 kbar is observed to induce the F-AF phase transition in the ferromagnetically ordered compound with x = 0.13. The AF-F-AF phase evolution was revealed with increasing pressure in the AF-ordered alloy with x = 0.08.

Phase evolution in sonochemically synthesized Fe3+ doped BaTiO3 nanocrystallites: structural, magnetic and ferroelectric characterisation

2016 ◽  
Vol 18 (14) ◽  
pp. 9758-9769 ◽  
Author(s):  
Dimple P. Dutta ◽  
Mainak Roy ◽  
Nandita Maiti ◽  
Avesh K. Tyagi
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Phase Evolution ◽  
Ferroelectric Behaviour

Sonochemically synthesized Fe3+ doped BaTiO3 nanostructures exhibiting phase transition and room temperature ferromagnetic and ferroelectric behaviour.

Variations of structure and composition in magnesium incorporated hydroxyapatite/β-tricalcium phosphate

2006 ◽  
Vol 21 (2) ◽  
pp. 428-436 ◽  
Author(s):  
Hyun-Seung Ryu ◽  
Kug Sun Hong ◽  
Jung-Kun Lee ◽  
Deug Joong Kim
Keyword(s):  
Phase Transition ◽  
Tricalcium Phosphate ◽  
Phase Evolution ◽  
Processing Parameters ◽  
Solubility Limit ◽  
Mode Analysis ◽  
X Ray Diffraction ◽  
Mg Addition ◽  
Tcp Phase ◽  
Mg Content

The phase evolution of magnesium incorporated hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) ceramics of high purity prepared by solid-state reaction was investigated with the aid of x-ray diffraction and infrared spectroscopy (IR) in transmittance mode analysis. The dependence of the microstructure on the phase evolution of biphasic ceramics during natural sintering was also investigated as a function of Mg content. When sintered at 1100 °C, Mg is preferentially incorporated into the β-TCP phase rather than the HA phase. This Mg incorporation into the β-TCP effectively suppresses the phase transition from β- to α-TCP. With increasing sintering temperature, the solubility limit of the Mg in the β-TCP decreases and Mg starts to be either incorporated into the HA phase or segregated as free MgO. The decreased Mg content in the β-TCP facilitates the phase transition from β- into α-TCP, at 1300 °C or higher. Different processing methods on Mg addition show that the retarded phase transition from β- to α-TCP is the inherent property of Mg-doped HA/TCP. The variations in processing parameters mainly affect the microstructure instead of the phase evolution, leading to highly densified HA/β-TCP ceramics.

scholarly journals Synthesis and characterization of nano-LaFeO3 powders by a softchemistry method and corresponding ceramics

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Phase Transition ◽  
Surface Area ◽  
Rhombohedral Phase ◽  
Phase Evolution ◽  
High Specific Surface Area ◽  
Coarse Grained ◽  
Complexing Agent ◽  
Porous Powder ◽  
Enthalpy Changes ◽  
Crystallite Sizes

The preparation of a nano-sized LaFeO3 powder by a soft-chemistry method usingstarch as complexing agent is described herein. Phase evolution and development of thespecific surface area during the decomposition process of (LaFe)-gels were monitored up to1000 °C. A phase-pure nano-sized LaFeO3 powder with a high specific surface area of 25.7m2/g and a crystallite size of 37 nm was obtained after calcining at 570 °C. TEMinvestigations reveal a porous powder with particles in the range of 20 to 60 nm. Calcinationsto 1000 °C result in crystallite sizes up to 166 nm. Dilatometric measurements of the sinteringbehaviour show that the beginning of shrinkage of pellets from the nano-sized powder is downshifted by more than 300 °C compared to coarse-grained mixed-oxide powder. The orthorhombic - rhombohedral phase transition was observed at 980 °C in DTAmeasurements for coarse-grained ceramic bodies. The enthalpy change (dH) during the phasetransition and the thermal expansion coefficient (adil) for ceramics was determined as 410 J/mol and 11.8×10-6 K-1, respectively. Whereas the enthalpy changes during the phase transition of the nano-sized LaFeO3 powders are £ 200 J/mol.

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