abstract
Composite powders comprising various proportions of beta-Tricalcium phosphate [beta-Ca-3(PO4)(2)] and a Alumina (alpha-Al2O3) were synthesized by wet precipitation and then heat treated for drying and crystalline phase development. The phase formation mechanism was assessed through a set of characterization techniques including XRD, FT-IR and Raman spectra, and quantitative Rietveld refinement analysis. Al2O3 additions delayed the transformation kinetics from calcium deficient apatite to beta-Ca-3(PO4)(2) and preserved the thermal stability of beta-Ca-3(PO4)(2) alpha-Al2O3 composites till 1400 C-omicron. Such enhancement of thermal stability was due to the occupancy of Al3+ at both Ca2+(4) and Ca2+(5) lattice sites of beta-Ca-3(PO4)(2). Beyond the occupancy saturation limit for Al3+, the excess of aluminium crystallized as alpha-Al2O3. Morphological analysis revealed the growth of rod-like alpha-Al2O3 platelets on the surface of micron sized beta-Ca-3(PO4)(2) grains. The mechanical data obtained from indentation of bulk composites displayed enhanced hardness and Young's modulus with increasing alpha-Al2O3 content in the composites. (C) 2017 Elsevier Ltd. All rights reserved.
keywords
BETA-TRICALCIUM PHOSPHATE; THERMAL-STABILITY; VIBRATIONAL PROPERTIES; ALUMINA COMPOSITES; ELASTIC PROPERTIES; BIPHASIC MIXTURES; ALPHA-ALUMINA; HYDROXYAPATITE; BONE; NANOPARTICLES
subject category
Materials Science
authors
Kumar, PN; Ferreira, JMF; Kannan, S
our authors
José Maria da Fonte Ferreira
Retired Professoracknowledgements
The authors are thankful to the financial support received from the Council of Scientific and Industrial Research, India (CSIR Scheme no. 22(612)/12/EMRII). The Instrumentation facility availed from the Central Instrumentation Facility (CIF) of Pondicherry University is greatly acknowledged. The support of CICECO-Aveiro Institute of Materials (Ref. UID/CTM/50011/2013), funded by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and the Portuguese Foundation for Science and Technology (FCT) is acknowledged. The authors also acknowledge Dr. Arunkumar Dhayalan, Assistant Professor, Department of Biotechnology, Pondicherry University for MTT analysis.