A new method of preparation of solid solutions of calcium and lead hydroxylapatites

Narasaraju, T. S. B.; Singh, Raghuvir; Rao, V. Laxminarasimha

doi:10.1016/0022-1902(72)80564-5

Cited by 26 publications

(14 citation statements)

References 9 publications

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“…According to Mtiller [40], Narasaraju et al [41], and Rao [42], the lattice parameters of these solid solutions both vary linearly 0171-967X/81/0033-0243 $01.00 with composition between those of the pure end members. On the contrary, Engel et al [43] found that the variation of the c parameter with composition deviates markedly from Vegard's law.…”

Section: Zincmentioning

confidence: 99%

Lattice parameters and cation distribution of solid solutions of calcium and lead hydroxyapatite

Verbeeck

Lassuyt

Heijligers³

et al. 1981

Calcif Tissue Int

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Summary. Solid solutions of calcium hydroxyapatite (CaOHA) and lead hydroxyapatite (PbOHA) of the formula Ca,0.x Pbx (PO4)6 (OH)2 were prepared by coprecipitation followed by heating at 800~ in a stream of CO2-free water vapor of 1 atm. The samples were apatitic in the range 0 < x < 6 and contained lead phosphates as a second phase at higher Pb/Ca ratios. Lattice parameters and cation distribution of the apatitic samples were determined by X-ray diffraction. The lattice parameters varied linearly with x in the range considered, whereas all Pb 2+ were located in the sixfold position for cations. There was a miscibility gap in the apatite series of solid solutions in the range 1 < x < 4, whereas apatites in the range 6 < x < 10 were not stable under the conditions of preparation. It is concluded that apatites in the range 4 < x < 6 represent a minimum in the free energy of solid solutions between CaOHA and PbOHA.

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Section: Zincmentioning

confidence: 99%

Lattice parameters and cation distribution of solid solutions of calcium and lead hydroxyapatite

Verbeeck

Lassuyt

Heijligers³

et al. 1981

Calcif Tissue Int

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“…Lead can substitute for calcium in the HA structure over the whole range of composition causing an enlargement of the unit cell. Although in earlier papers (Muller, 1947;Narasaraju, Singh & Rao, 1972;Rao, 1976) the lattice parameters of lead-calcium hydroxyapatite were reported to vary linearly with the composition, more recently deviations of the c parameter from Vegard's law have been observed (Engel, Krieg & Reif, 1975;Verbeeck, Lassuyt, Heijligers, Driessens & Vrolijk, 1981; Andres-Verges, Higes-Rolando, Valenzuela-Calahorro & GonzaJez-Diaz, 1983). The observed deviations from Vegard's law have been attributed to a possible preference of the Pb 2+ ion for site (2) of the apatite structure, on the basis of the cation distribution deduced from the relative intensities of suitable reflections in the powder diffractogram Furthermore, the structure analysis of a sample of Pb9(PO4) 6 prepared by hydrothermal reaction (Hata, Marumo, Iwai & Aoki, 1980) revealed a deficiency of lead in site (1).…”

Section: Introductionmentioning

confidence: 98%

Structure refinements of lead-substituted calcium hydroxyapatite by X-ray powder fitting

Bigi¹,

Ripamonti²,

Brückner³

et al. 1989

Acta Crystallogr Sect B

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The crystal structures of hydroxyapatites, synthesized at different degrees of lead substitution for calcium (20, 45 and 80% Pb atoms) by solid-state reaction at 1173 K, have been investigated by X-ray powder-pattern fitting. The disagreement factors (Rwp) are 5.9, 6.0 and 6-6% for Pb20, Pb45 and Pb80, respectively. The site-occupancy factors of Pb atoms indicate a clear preference of lead for site (2) of the apatite structure,

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“…Intensive research in HA involving a wide range of powder processing techniques, composition and experimental conditions have been investigated with the aim of determining the most effective synthesis method and conditions to produce well-defined particle morphology [10][11][12]. Among the available synthesis methods, wet precipitation technique, which involves aqueous solutions, is most widely used by many researchers [13]. The advantages of this process are that the by-product is almost water and the probability of contamination during processing is reported to be very low [14].…”

Section: Introductionmentioning

confidence: 99%

Consolidation of nanocrystalline hydroxyapatite powder

Ramesh

Tan

Sopyan

et al. 2007

Science and Technology of Advanced Materials

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The effect of sintering temperature on the sinterability of synthesized nanocrystalline hydroxyapatite (HA) was investigated. The starting powder was synthesized via a novel wet chemical route. HA green compacts were prepared and sintered in atmospheric condition at various temperatures ranging from 900-1300 1C. The results revealed that the thermal stability of HA phase was not disrupted throughout the sintering regime employed. In general, the results showed that above 98% of theoretical density coupled with hardness of 7.21 GPa, fracture toughness of 1.17 MPa m 1/2 and Young's modulus of above 110 GPa were obtained for HA sintered at temperature as low as 1050 1C. Although the Young's modulus increased with increasing bulk density, the hardness and fracture toughness of the sintered material started to decline when the temperature was increased beyond 1000-1050 1C despite exhibiting high densities 498% of theoretical value. The occurrence of this phenomenon is believed to be associated with a thermal-activated grain growth process. r

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A new method of preparation of solid solutions of calcium and lead hydroxylapatites

Cited by 26 publications

References 9 publications

Lattice parameters and cation distribution of solid solutions of calcium and lead hydroxyapatite

Lattice parameters and cation distribution of solid solutions of calcium and lead hydroxyapatite

Structure refinements of lead-substituted calcium hydroxyapatite by X-ray powder fitting

Consolidation of nanocrystalline hydroxyapatite powder

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