Zur Kenntnis der Phosphate I: Über Hydroxylapatit.

Rathje, Werner

doi:10.1002/jpln.19390120109

Cited by 39 publications

(15 citation statements)

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“…HA is synthesized by widely reported suspension-precipitation route [11,12]. HA powders were then calcined at 1073 K for 2 hrs and the XRD peaks confirmed the pure hydroxyapatite phase.…”

Section: Materials Synthesismentioning

confidence: 99%

Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites

et al. 2011

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In order to mimic the electrical properties of natural bone, the present work investigated the dielectric, AC conductivity, pyroelectric and piezoelectric properties of HA-40 wt% BaTiO 3 (HA-26 vol% BaTiO 3 ) and HA-60 wt% BaTiO 3 (HA-44 vol% BaTiO 3 ) composites. Multistage spark plasma sintering was used to achieve the desired combination of properties. The electrical parameters were measured as a function of temperature and frequency. The values of dielectric constant and loss for both the developed composites, measured at room temperature and at 1 KHz frequency was 21, 38 and 0.01 and 0.02, respectively. The AC conductivity for both the composites is found to be of the order of 10 −10 and 10 −9 ( cm) −1 , measured under similar conditions. Activation energy calculated from σ ac vs. temperature plot for HA-40 wt% BaTiO 3 is 0.50 eV. The room temperature pyroelectric coefficients for both the compositions are 2.35 and 21 µC/m 2 K, respectively. The piezoelectric coefficient values (d 33 ) for both the compositions are 0.9 and 1 pC/N, respectively. The observed values of electrical parameters closely resemble with that of the natural human bone.

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“…HA is synthesized by widely reported suspension-precipitation route [11,12]. HA powders were then calcined at 1073 K for 2 hrs and the XRD peaks confirmed the pure hydroxyapatite phase.…”

Section: Materials Synthesismentioning

confidence: 99%

Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites

et al. 2011

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“…10 In one of the earlier studies, it was observed that 10 wt% phosphate glass addition to HAp-composites led to a partial dissociation of HAp to TCP. 11 With an aim to develop lightweight biocompatible material, the choice of mullite as a ceramic reinforcement has been made in the present work, because of the fact that mullite has a lower density (3.06 g/cm 3 ) and a higher hardness (12)(13)(14)(15) GPa) than HAp and a moderate fracture toughness (B3 MPa Á m 0.5 ). Mullite, an important structural ceramic material, is a compound with larger solubility of silica in alumina and has been investigated for a long time as a refractory material.…”

Section: Introductionmentioning

confidence: 99%

Sintering, Phase Stability, and Properties of Calcium Phosphate‐Mullite Composites

Nath

Biswas

Wang

et al. 2010

Journal of the American Ceramic Society

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In this contribution, we report the results of a study to probe into the combined effect of the sintering conditions and mullite (3Al2O3·2SiO2) addition (upto 30 wt%), on the densification mechanism, phase assemblage, and microstructure development in calcium phosphate (CaP)‐mullite composites. The experimental results reveal that close to 95% theoretical density can be achieved by sintering the compositions in the temperature range of 1300°–1350°C. Finer scale microstructural analysis using transmission electron microscopy reveals the presence of both β‐ and α‐TCP (Ca3(PO4)2–tricalcium phosphate) and a crystalline residue of gehlenite at triple junctions. The shrinkage kinetics of the composites have been analyzed to qualitatively understand the sintering mechanisms. For the composites, solid‐state sintering in the initial stage, followed by liquid‐phase sintering at or near the sintering temperature are postulated to explain the effect of temperature and volume fraction of the second phase. Some important features of the liquid‐phase sintering have been discussed using the CaO–Al2O3–SiO2 ternary phase diagram. A comparison with the earlier published results reveals that a better combination of long‐crack fracture toughness, compressive strength, and flexural strength can be obtained with the newly developed composites.

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“…Initially proposed by Rathje in 1939 [25], the method was studied for different types of precursors in an attempt to obtain reproducible results [5,6,11,13,[16][17][18]26]. To date, the correlation between the synthesis parameters and the material characteristics is poorly understood, so further research is needed for adapting the method for advanced manufacturing.…”

Section: Introductionmentioning

confidence: 99%

Biomimetic Calcium Phosphates Derived from Marine and Land Bioresources

Miculescu¹,

Mocanu²,

Maidaniuc³

et al. 2018

Hydroxyapatite - Advances in Composite Nanomaterials, Biomedical Applications and Its Technological Facets

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This chapter aims to establish the key factors for technological optimization of biogenic calcium phosphate synthesis from marine and land resources. Three natural calcium sources-marble, seashell and bovine bone-were considered as raw materials. The proposed materials are suitable candidates for the synthesis of bone substitutes similar to the inorganic bone component. The synthesis processes were developed based on the investigations of thermal phenomena (TGA-DSC analysis) that can occur during thermal treatments. By this method, we were able to determine the optimum routes and temperatures for the complete dissociation of calcium carbonate as well as risk-free deproteinization of bovine bone. An exhaustive characterization, performed with modern and complementary techniques such as morphology (SEM), composition (EDS, XRF) and structure (FT-IR, XRD), is presented for each precursor. The final chemical composition of ceramic products can be modulated through a careful control of the key parameters involved in the conversion, in order to create long-term performant biphasic apatite biomaterials, with broad medical applicability. Identifying the suitable strategies for this modulation contributes to an appreciable advance in orthopedic tissue engineering.

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Zur Kenntnis der Phosphate I: Über Hydroxylapatit.

Cited by 39 publications

References 0 publications

Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites

Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites

Sintering, Phase Stability, and Properties of Calcium Phosphate‐Mullite Composites

Biomimetic Calcium Phosphates Derived from Marine and Land Bioresources

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Zur Kenntnis der Phosphate I: Über Hydroxylapatit.

Cited by 39 publications

References 0 publications

Dielectric and Pyroelectric Properties of HAp-BaTiO3Composites

Dielectric and Pyroelectric Properties of HAp-BaTiO3Composites

Sintering, Phase Stability, and Properties of Calcium Phosphate‐Mullite Composites

Biomimetic Calcium Phosphates Derived from Marine and Land Bioresources

Contact Info

Product

Resources

About

Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites

Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites