Growth Orientation of the Mechanosynthesized Fluorapatite-Based Composite Nanopowders: Influence of Subsequent Thermal T
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Growth Orientation of the Mechanosynthesized Fluorapatite-Based Composite Nanopowders: Influence of Subsequent Thermal Treatment Bahman Nasiri-Tabrizi • Abbas Fahami
Received: 1 April 2013 Ó Springer Science+Business Media New York 2013
Abstract Growth orientation of fluorapatite–zirconia nanopowders was investigated after mechanical activation and thermal annealing process in the range of 600–1,300 °C for 1 h. Results revealed that during heating of the composite nanopowders the transition of the monoclinic zirconia to tetragonal form and its stabilization by calcium fluoride originating from the decomposition of fluorapatite as well as the formation of a solid solution of calcium fluoride in zirconia occurred. The influence of annealing on the growth orientation of fluorapatite–zirconia composite nanopowders indicated that the crystal growth of fluorapatite was preferentially accentuated on the (002) face in the direction of the crystallographic c-axis after heat treatment. Based on FE–SEM observations, the experimental outcome was composed of both agglomerates and fine particles (*33 nm) after 600 °C, while annealing of the sample at 1,300 °C demonstrated the occurrence of abnormal grain growth. Keywords Fluorapatite–zirconia composite Growth orientation FE–SEM observation Thermal treatment
Introduction Bioceramics became an accepted group of materials for medical applications, mainly for implants in orthopaedics, maxillofacial surgery and dental implants [1]. Recently, the fluoridated hydroxyapatite [fluorhydroxyapatite; FHAp (Ca10(PO4)6(OH)2-2x F2x)/fluorapatite; FAp (Ca10(PO4)6F2)] has gained much attention in the area of biomedical applications because of their chemical and biological properties [2, 3]. On B. Nasiri-Tabrizi (&) A. Fahami Materials Engineering Department, Najafabad Branch, Islamic Azad University, Najafabad, Isfahan, Iran e-mail: [email protected]
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B. Nasiri-Tabrizi, A. Fahami
the other hand, the incorporation of bioinert ceramics into calcium phosphate-based materials has demonstrated significant improvement in mechanical properties without substantial compromise in biocompatibility. Some attempts have been made to develop hydroxyapatite (HAp) and FHAp-based composites such as: HAp–Al2O3 [4], HAp–ZrO2 [5, 6], HAp–TiO2 [7], FHAp–Al2O3 [8], and FHAp–ZrO2 [9, 10] composites. Among the second phases, ZrO2 has been studied extensively because of its relatively higher mechanical strength and toughness [5, 6]. Since the nanocrystalline structure compared to the microcrystalline structure is more important to achieve high thermal stability and mechanical properties [11], synthesize of FAp– ZrO2 composite nanopowders with appropriate structural features via one step mechanochemical process provided the main purpose for current research. To date, mechanochemical synthesis is well known for the production of a wide range of novel advanced materials such as nanocomposites. In the field of nanocomposites, this technique can lead to the formation of interpenetrating phase composi
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