Influence des ajouts sur la densification et la microstructure de la fluorapatite substituée au magnésium

Hidouri, Mustapha; Bouzouita, Khaled; Fattah, Nabil

doi:10.3166/acsm.30.133-148

Cited by 3 publications

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“…After the dissolution of the apatite up to saturation, facilitated probably by its high solubility, there was a crystallization of the needle-like crystals, which hindered the densification. Such a process was observed for magnesium-substituted fluorapatite sintered with additives [44].…”

Section: Sintering Of Powdersmentioning

confidence: 83%

“…The shrinkage curves of these samples (not shown here) exhibited an expansion at about 1100˚C. This expansion was due to the formation of a liquid phase resulting from an eutectic between apatite and fluorite, which was probably present in the as-synthesized powder as impurity [42][43][44]. As fluorine content was increased, the amount of the liquid phase seemed to increase (Figure 7(c), MFA), causing the distortion of the samples.…”

Section: Sintering Of Powdersmentioning

confidence: 99%

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Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Nsar¹,

Hassine²,

Bouzouita³

2013

JBNB

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Biological apatites contain several elements as traces. In this work, magnesium and fluorine co-substituted hydroxyapatites with the general formula Ca 9 Mg(PO 4 ) 6 (OH) 2-y F y , where y = 0, 0.5, 1, 1.5 and 2 were synthesized by the hydrothermal method. After calcination at 500˚C, the samples were pressureless sintered between 950˚C and 1250˚C. The substitution of F − for OH − had a strong influence on the densification behavior and mechanical properties of the materials. Below 1200˚C, the density steeply decreased for y = 0.5 sample. XRD analysis revealed that compared to hydroxylfluorapatite containing no magnesium, the substituted hydroxyfluorapatites decomposed, and the nature of the decomposition products is tightly dependent on the fluorine content. The hardness, elastic modulus and fracture toughness of these materials were investigated by Vickers's hardness testing. The highest values were 622 ± 4 GPa, 181 ± 1 GPa and 1.85 ± 0.06 MPa·m 1/2 , respectively.

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Section: Sintering Of Powdersmentioning

confidence: 83%

Section: Sintering Of Powdersmentioning

confidence: 99%

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Nsar¹,

Hassine²,

Bouzouita³

2013

JBNB

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“…Then the pellets were sintered, as in the case of the magnesium-substituted FAp [22], under argon flow at 900˚C and 1000˚C for 1 h. The heating and cooling rate was of 10˚C min −1 . The sintered samples were characterized based on relative density, X-ray diffraction analysis using a Philips PW 1710 diffractometer and on microstructural analysis using a scanning electron microscope (PHILIPS XL 30).…”

Section: Methodsmentioning

confidence: 99%

“…This phase might be the product of the reaction between the additives and the FAp, according to the chemical equations cited in a previous work [22]. SEM micrographs of the fracture surfaces of samples sintered at 900˚C and 1000˚C are shown in Figure 4.…”

Section: ) Sodium Additivesmentioning

confidence: 99%

“…All these properties and others encouraged several researchers to fabricate porous ceramics and composites of FAp [14] [15] [16] [17] [18], while others have been interested in studying glasses ceramics containing FAp [19] [20]. For our work, we studied the effect of magnesium-calcium substitution on the properties of FAp [21] [22] [23] [24]; we also studied the sintering of the FAp containing magnesium in the presence of additives such as Li 2 CO 3 , NaF, Na 2 CO 3 , Na 3 PO 4 , KCl, K 2 CO 3 , CaF 2 , CaCl 2 and MgCl 2 [22]. The purpose of the present study is also to examine the sintering behavior of FAp in the presence of the mentioned sintering additives.…”

Section: Introductionmentioning

confidence: 99%

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Densification and Microstructure of Fluorapatite Sintered with Alkaline and Alkaline-Earth Additives

Hidouri¹,

Tahar²,

Bouzouita³

2018

MSCE

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A study was performed to investigate the effect of some selected sintering additives on the densification and microstructure of fluorapatite (FAp, Ca 10 (PO 4 ) 6 F 2 ). The sintering aids, used for improving the material densification at lower than 1080˚C temperature, were classified according to their cations as alkaline such as Li 2 CO 3 , NaF, Na 2 CO 3 , Na 3 PO 4 , KCl, K 2 CO 3 , and alkaline-earth such as CaF 2 , CaCl 2 and MgCl 2 . Amounts of 0.1; 1 and 3 wt% were vigorously homogenized with FAp powders then the solid mixture was pressurelessly sintered under argon flow with 10˚C•min −1 heating and cooling speed. The density of each sintered material was determined by calculation of the pellet dimension and weight, the crystalline phases were identified using X-ray diffraction (XRD) and the phase morphology was examined by scanning electron microscopy (SEM). The dependence of densification and microstructure on sintering temperature range 900˚C -1000˚C and amount of sintering aids was studied. It was found that all sintering additives were able to ameliorate the sintrability of the material at temperatures 900˚C and 1000˚C. Maximums of about 96% were reached with adequate amounts and sintering temperatures. An exception was found with KCl which had no effect on the density. The microstructures of sintered specimens strictly follow the densification ratios and the sintering mechanism depended on the melting point of the additive.

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Sintering Behavior of Magnesium-Substituted Fluorapatite Powders Prepared by Hydrothermal Method

Nasr

Bouzouita

2011

Bioinorganic Chemistry and Applications

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Magnesium-substituted fluorapatite powders were synthesized by hydrothermal method, and their sintering behavior was investigated by dilatometry in the temperature range 25–1100°C. Analysis of the obtained powders by X-ray diffraction and 31P NMR spectroscopy showed that the powders consisted of a single apatite phase and no amorphous phase has been formed. Compared to pure fluorapatite, the shrinkage of the substituted samples occurred in two steps and the temperature at which the sintering rate was maximum is lower. In addition, the shrinkage was interrupted by an expansion of the samples due to the formation of a liquid phase. The latter phase led to the crystallization of needle-crystals by a dissolution-diffusion-reprecipitation process.

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Influence des ajouts sur la densification et la microstructure de la fluorapatite substituée au magnésium

Cited by 3 publications

References 0 publications

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Densification and Microstructure of Fluorapatite Sintered with Alkaline and Alkaline-Earth Additives

Sintering Behavior of Magnesium-Substituted Fluorapatite Powders Prepared by Hydrothermal Method

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