A generalized geometric approach to anisotropic peak broadening due to domain morphology

Ectors, Dominique; Goetz-Neunhoeffer, F.; Neubauer, J.

doi:10.1107/s1600576714026557

Cited by 67 publications

(59 citation statements)

References 16 publications

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“…Development of the model ellipsoid volume (a) and final values of the model ellipsoid volume (b) used as measure for crystallite volume development of CDHA forming in partially amorphized α‐TCP samples with different Sr 2+ contents, determined according to Ectors et al; a 0.2 M Na 2 HPO 4 solution was used as mixing liquid; w/c = 1; T = 23°C.…”

Section: Resultsmentioning

confidence: 99%

“… Determined from quantitative in‐situ XRD measurements according to the method of Ectors et al; the values are means from three independent measurements. …”

Section: Resultsmentioning

confidence: 99%

“…Model ellipsoid for refinement of the anisotropic crystallite size of CDHA according to Ectors et al The model for the hexagonal CDHA crystallite in the graphic was created with VESTA …”

Section: Methodsmentioning

confidence: 99%

“…Due to the anisotropic crystallinity of the CDHA which formed during hydration of the a-TCP powder samples, an acceptable fit could not be obtained using a single crystallite size. Hence, the approach of Ectors et al 17 was applied for refinement of anisotropic crystallite sizes. In this method, the shapes of the crystallites are simulated by suitable geometric models.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Sr²⁺ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

2015

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Hydration of partially amorphized a-TCP powders with Sr 2+ concentrations ranging from 0 to 10 mol% substitution for Ca 2+ was analyzed by isothermal calorimetry and quantitative in-situ XRD. Hydration of both crystalline a-TCP and amorphous TCP (ATCP) forming CDHA was retarded to an increasing extent with increasing Sr 2+ content. Sr 2+ slightly reduced the crystallite size (XRD coherent scattering domains) of the CDHA formed during hydration, while the size of crystals visible under SEM was not noticeably affected. Reaction enthalpies of DH R(Sr-a-TCP?Sr-CDHA) = 122 AE 8 J/g TCP and DH R(Sr-ATCP?Sr-CDHA) = 257 AE 8 J/g TCP were determined for the hydration of crystalline a-TCP and ATCP containing 5 mol% Sr 2+ substitution for Ca 2+ . This is comparable with the corresponding reaction enthalpies previously obtained for undoped samples, which are 106 AE 7 J/g TCP for a-TCP and 250 AE 7 J/g TCP for ATCP.

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Section: Resultsmentioning

confidence: 99%

“… Determined from quantitative in‐situ XRD measurements according to the method of Ectors et al; the values are means from three independent measurements. …”

Section: Resultsmentioning

confidence: 99%

“…Model ellipsoid for refinement of the anisotropic crystallite size of CDHA according to Ectors et al The model for the hexagonal CDHA crystallite in the graphic was created with VESTA …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Sr²⁺ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

2015

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“…The anisotropic crystallinity of CDHA was refined using the approach of Ectors et al [18]. A triaxial ellipsoid was chosen, as it resulted in the best fits.…”

Section: Quantification Of Samples A昀ter Calorimetrymentioning

confidence: 99%

Hydration enthalpy of amorphous tricalcium phosphate resulting from partially amorphization of β-tricalcium phosphate

2017

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Abstract:As it was recently shown that β-tricalcium phosphate (β-TCP), similar to α-TCP, can be mechanically activated by prolonged ball milling, partially amorphized β-TCP is promising for the development of new bone cement formulations. Hence in the present study the hydration of partially amorphized β-TCP with different contents of an amorphous phase (amorphous tricalcium phosphate, ATCP) was investigated by isothermal calorimetry and quantitative X-ray diffraction (XRD) to obtain the hydration enthalpies of β-TCP and ATCP. Measurements were conducted at 23°C, a 0.1 M Na 2 HPO 4 aqueous solution was used as mixing liquid. For the hydration enthalpy of crystalline β-TCP, a value of ΔH R(β-TCP → CDHA) = −23.9 kJ/mol TCP can be calculated from literature data. In this study ΔH R(ATCP → CDHA) = −83 ± 6 kJ/mol TCP was determined from new measurement results for the hydration of amorphized β-TCP to calcium-deficient hydroxyapatite (CDHA). Hence the hydration enthalpy was shown to be increased by a factor of 3.5 due to amorphization. Additionally, the hydration enthalpy of ATCP resulting from amorphization of β-TCP was compared and demonstrated to be not significantly different to that of ATCP resulting from α-TCP amorphization, which was −78 ± 2 kJ/mol TCP . This indicates that amorphization of α-TCP and β-TCP results in an amorphous phase with the same properties.

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Aqueous Calcium Phosphate Cement Inks for 3D Printing

Weichhold,

Pfeiffle,

Kade

et al. 2023

Adv Eng Mater

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Mimicking the native properties and architecture of natural bone is a remaining challenge within the field of regenerative medicine. Due to the chemical similarity of calcium phosphate cements (CPCs) to bone mineral, these cements are well studied as potential bone replacement material. Nevertheless, the processing and handling of CPCs into prefabricated pastes with adequate properties for 3D printing has drawbacks due to slow reaction times, limited design freedom, as well as fabrication issues such as filter pressing during ejection through thin nozzles. Here, an aqueous cement paste containing α‐TCP powder is proposed, which is stabilized by sodium pyrophosphate (Na4P2O7·10H2O) as additive. Since high powder loadings within pastes can result in filter pressing during extrusion, various concentrations and molecular weights of hyaluronic acid (HyAc) were added to the cement paste, resulting in reduced filter pressing during 3D extrusion‐based printing. These cement pastes were investigated regarding their setting reaction after activation with orthophosphate solution by isothermal calorimetry and X‐ray diffraction, as well as their hardening performance using Imeter measurements, while the processability was assessed by extrusion through 1.19 mm and 0.84 mm cannulas. 3D printed structures with appropriate HyAc molecular weight and concentration demonstrate suitable mechanical properties and resolution for clinical application.This article is protected by copyright. All rights reserved.

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A generalized geometric approach to anisotropic peak broadening due to domain morphology

Cited by 67 publications

References 16 publications

Influence of Sr²⁺ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

Influence of Sr²⁺ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

Hydration enthalpy of amorphous tricalcium phosphate resulting from partially amorphization of β-tricalcium phosphate

Aqueous Calcium Phosphate Cement Inks for 3D Printing

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A generalized geometric approach to anisotropic peak broadening due to domain morphology

Cited by 67 publications

References 16 publications

Influence of Sr2+ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

Influence of Sr2+ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

Hydration enthalpy of amorphous tricalcium phosphate resulting from partially amorphization of β-tricalcium phosphate

Aqueous Calcium Phosphate Cement Inks for 3D Printing

Contact Info

Product

Resources

About

Influence of Sr²⁺ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP

Influence of Sr²⁺ on Calcium‐Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α‐TCP