Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-27T02:05:59.140Z Has data issue: false hasContentIssue false
  • English
  • Français

Sintering of HAp precipitated from solutions containing ammonium nitrate and PVA

Published online by Cambridge University Press:  26 February 2011

Tatiana Victorovna Safronova ,
Valery I. Putlyaev ,
Alexey V. Belyakov  and
Mikhail A. Shekhirev
Tatiana Victorovna Safronova
Affiliation:
[email protected], MSU, Chemical Department, Leninskie Gory, 1, Moscow, N/A, N/A, Russian Federation, 7 (095) 9395245, 7 (095) 9390998
Valery I. Putlyaev
Affiliation:
[email protected], MSU, Chemical Department, Russian Federation
Alexey V. Belyakov
Affiliation:
[email protected], MUCTR, Department of Chemical Technology of Silicates, Russian Federation
Mikhail A. Shekhirev
Affiliation:
[email protected], MSU, Department of material science
Get access

Abstract

Bioceramics based on hydroxyapatite (HAp) is known to be a prospective material for biomedical applications. However, sintering of HAp is still understudied in sense of reasonable selection of controlling parameters. In particular, the role of impurities and co-products of powder fabrication is still questionable. The data concerning the role of ammonium nitrate coming to precipitated HAp from the mother liquor, its effect on powder compaction and subsequent sintering, are not available.

Nanosized powders of HAp were fabricated via conventional wet-precipitation technique by dropwise adding of Ca(NO3)2 solution (0.25 -1.67 M) to the stock solution of (NH4)2HPO4 (0.15-1.00 M) with pre-adjusted pH at 60°C in presence of polyvinyl alcohol (PVA). PVA was added to the stock solution in order (i) to block crystal growth during synthesis , (ii) to improve stability of Hap suspension to sedimentation, (iii) to regulate an aggregation of HA nanoparticles during synthesis and in the stage of drying.

NH4NO3 – a by-product of the precipitation reaction, presented in as-precipitated powder in amount of 30%, was evaluated as an additive affecting a compaction of the powder and the initial stage of a sintering. The powder samples were tested by XRD, FTIR, light-scattering , TEM and SEM/EDX to get particle sizes, morphology and chemical composition, dilatometry. Ceramics were sintered at 700-1250°C and evaluated with SEM/EDX and density measurements.

Addition of PVA to the stock solution in the course of HAp precipitation is a promising technique to control an aggregation of HAp nanoparticles in the stages of drying and sintering. PVA acting as a surfactant in the solution and as a binder in dry powder can keep highly reactive small HAp particles within large agglomerates providing better molding of the powder and controllable densification of ceramics. The effect of PVA on microstructure of the HAp powder and their sintering behaviour is discussed in terms of self-organisation concept and synergetics.

Keywords

powdersinteringmicrostructure
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 887: Symposium Q – Degradation Processes in Nanostructured Materials , 2005 , 0887-Q06-10
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Hench, L.L., “Bioceramics: From Concept to Clinic”, J. Am. Ceram. Soc., 74 1487–510 (1991)Google Scholar
2. Ying, , et al. Nanocrystalline apatites and composites, prostheses incorporating them, and method for their production, United States Patent, 2000, 6, 013, 591 Google Scholar
3. Raynaud, S., Champion, E., Bernache-Assollant, D., Thomas, P. “Calcium phosphate apatites with variable Ca/P atomic ratio I. Sinthesis, Characterisation and thermal stability of powders”, Biomaterials 23, 1065–1072 (2002).Google Scholar
4. Balkevich, V.L., Belyakov, A.V., Safronova, T.A. “Synthesis of disaggregated fine mullite powder by meanse of chemical methods” Steklo I keramika, º5, 25–27 (1985), (in Russian).Google Scholar
5. Ombretta, Massala and Seshardi, Ram. “Synthesis Routes for Large Volumes of nanoparticles” Annu. rev. Mater. Res. 34, 41–81 (2004).Google Scholar
6. Si, Satyabrata, Kotal, Atanu, Mandal, Tarun K., Giri, Saurav, Nakamura, Hiroyuki, and Kohara, Takao, “Size-Controlled Synthesis of Magnetite Nanoparticles in the presence of Polyelectrolytes” Chem. Mater. 16, 3489–3496 (2004).Google Scholar
7. Belyakov, A.V. “Methods of preparation of inorganic nonmetallic nanoparticles” (MCTUR, Moscow, 2003), 80 p (in Russian).Google Scholar
8. Amid, Z. “The influence of Polyphosphates, Phosphonates, and poly(carboxylic acids) on Crystal Growth of hydroxyapatite” Langmuir 3, 1063–1069 (1987)Google Scholar
9. Belyakov, A.V., Yenko, A.S., “Regions of Local Densification and their Role in Ceramics. Analysis of Fracture Surfaces as Simple Tool to Study the Local Densification Regions in Oxide Ceramics, Fracture Mechanics of Ceramics” V. 13. Crack-Microstructure Intyeraction, R-Curve Behavior, Enviromental Effect in Fracture, and Standartization. (N-Y., Boston, Dordrecht, London, Moscow: Kluwer Academic/Plenum Publishers, 2002) - 529 p. - P. 497–502.Google Scholar
10. Belyakov, A.V., “Principal Bifurcations in Firing of Compact Oxide ceramics”, Glass and Ceramics 57, Nº 10, 345–349 (2000)Google Scholar
11. Prigogine, I., The End of Certitude. (Free Press, N.Y.1997).Google Scholar
12. Belyakov, A.V., “Synergetic and Quasichemical Approaches in Ceramic Technology” (a Review) Glass and Ceramics. 60, Nº 9 – 10, 274–279 (2003).Google Scholar
13. Raynaud, S., Champion, E., Bernache-Assollant, D., Thomas, P., “Calcium phosphate apatites with variable Ca/P atomic ratio II. Calcination and sintering”, Biomaterials, 23, 1073–1080 (2002).Google Scholar