Sintering Effects on Morphology, Thermal Stability and Surface Area of Sol-Gel Derived Nano-Hydroxyapatite Powder

Journal Article · Mon Dec 12 04:00:00 EST 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3653766· OSTI ID:21612359

Kapoor, Seema ^[1]; Batra, Uma ^[2]; Kohli, Suchita ^[3]

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1. University Institute of Chemical Engineering and Technology, Panjab University, Chandigarh (India)
2. Department of Materials and Metallurgical Engineering, PEC University of Technology, Chandigarh (India)
3. University Institute of Chemical Engineering and Technology, Panjab University, Chd. (India)

Hydroxyapatite (HAP) ceramics have been recognized as substitute materials for bone and teeth in orthopedic and dentistry field due to their chemical and biological similarity to human hard tissue. The nanosized and nanocrystalline forms of HAP have great potential to revolutionize the hard tissue-engineering field, starting from bone repair and augmentation to controlled drug delivery systems. This paper reports the synthesis of biomimetic nano-hydroxyapatite (HAP) by sol-gel method using calcium nitrate tetrahydrate (CNT) and potassium dihydrogen phosphate (KDP) as calcium and phosphorus precursors, respectively to obtain a desired Ca/P ratio of 1.67. Deionized water was used as a diluting media for HAP sol preparation and ammonia was used to adjust the pH to 11. After aging, the HAP gel was dried at 55 deg. C and sintered to different temperatures (200 deg. C, 400 deg. C, 600 deg. C, 800 deg. C, 1000 deg. C and 1200 deg. C). The dried and sintered powders were characterized for phase composition using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The particle size and morphology was studied using transmission electron microscopy (TEM). The thermal behavior of the dried HAP nanopowder was studied in the temperature range of 55 deg. C to 1000 deg. C using thermal gravimetric analyser (TGA). The BET surface area of absorbance was determined by Nitrogen adsorption using Brunauer-Emmett-Teller (BET) method. The presence of characteristic peaks of the phosphate and OH groups in FTIR spectrums confirmed the formation of pure HAP in dried as well as sintered powders. XRD results also confirmed the formation of stoichiometric nano-HAP. Sintering revealed that with increase in temperature, both the crystallinity and crystallite size of nano-HAP particles increased. The synthesized nano-HAP powder was found to be stable upto 1000 deg. C without any additional phase other than HAP, whereas peak of {beta}-TCP (tricalcium phosphate) was observed at 1200 deg. C. Photomicrograph of TEM showed that the nanopowder sintered at 600 deg. C is composed of hydroxyapatite nanoparticles (26.0-45.6 nm), which is well in agreement with the crystallite size calculated using XRD data. TGA study showed the thermal stability of the synthesized nano-HAP powder. The BET surface area decreased with increase in sintering temperature.

• OSTI ID: 21612359
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1393; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ADSORPTION
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
AMMONIA
APATITES
CALCIUM
CALCIUM COMPOUNDS
CALCIUM NITRATES
CALCIUM PHOSPHATES
CERAMICS
CHEMICAL ANALYSIS
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
FABRICATION
FOURIER TRANSFORMATION
GRAVIMETRIC ANALYSIS
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED SPECTRA
INTEGRAL TRANSFORMATIONS
METALS
MICROSCOPY
MINERALS
NANOSTRUCTURES
NITRATES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PHOSPHATE MINERALS
PHOSPHATES
PHOSPHORUS COMPOUNDS
POTASSIUM COMPOUNDS
POTASSIUM PHOSPHATES
POWDERS
QUANTITATIVE CHEMICAL ANALYSIS
SCATTERING
SINTERING
SIZE
SOL-GEL PROCESS
SORPTION
SPECTRA
SURFACE AREA
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSFORMATIONS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION