Busca avançada
Ano de início
(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Sol-gel synthesis, structure, sintering and properties of bioactive and inert nano-apatite-zirconia glass-ceramics

Texto completo
Montazerian, Maziar [1] ; Schneider, Jose Fabian [2] ; Yekta, Bijan Eftekhari [1] ; Marghussian, Vahak Kaspari [1] ; Rodrigues, Alisson Mendes [3] ; Zanotto, Edgar Dutra [3]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Iran Univ Sci & Technol, Sch Met & Mat Engn, Tehran 1684613114 - Iran
[2] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13566590 Sao Carlos, SP - Brazil
[3] Univ Fed Sao Carlos, Dept Mat Engn, Ctr Res Technol & Educ Vitreous Mat CeRTEV, BR-13565905 Sao Carlos, SP - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: CERAMICS INTERNATIONAL; v. 41, n. 9, A, p. 11024-11045, NOV 2015.
Citações Web of Science: 25

We synthesized four glasses of the system 61.2SiO(2)-(24.3-x)CaO-4.5P(2)O(5)-10ZrO(2)-xK(2)O (x=0, 2, 4, 6 mol% = Ca replaced by K) using a sol-gel route and compared their properties with a 68SiO(2)-27CaO-5P(2)O(5) (mol%) Zr-free base glass. Their structure, sintering and crystallization behavior were investigated with the aim of converting the gel-glasses into dense glass ceramics. Then, the in vitro bioactivity and mechanical properties of the optimized sintered samples were characterized. The structure of the gel-glasses was investigated by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution transmission electron microscopy (HR-TEM). The sintering and crystallization kinetics of the glasses were studied by hot stage microscopy (HSM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The microstructures of the resulting glass ceramics were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with energy dispersive spectroscopy (EDS). The apatite-forming ability of the sintered glass-ceramics in simulated body fluid (SBF) was investigated using FTIR spectroscopy and SEM. The three-point bending strength, Vickers microhardness and fracture toughness were also measured. Structural analysis by NMR and FTIR revealed that Zr acts as a glass former and K is a modifier, as expected. The K2O addition strongly improved the material's sinterability, e.g., 2 mol% K2O decreased the optimum sintering temperature from 1300 degrees C to 1050 degrees C. Uniformly dispersed ZrO2 nanocrystals, with particle sizes of 25-55 nm, were precipitated in the glass-ceramics. In vitro bioactivity tests confirmed that the K2O-free glass-ceramics (partially sintered at 1000 degrees C) were bioactive and hydroxycarbonate apatite (HCA) grew on their surface after 24 h in SBF. However, the > 90% dense glass-ceramics with various contents of K2O exhibited low solubility and a much smaller tendency toward HCA formation. Improvement of some mechanical properties was observed for the sample containing 2 mol% K2O, in which apatite and zirconia crystallized. The 3p-bending strength and fracture toughness of the 94% dense sample were approximately 140 MPa and 2 MPa m(1/2), respectively. We propose that crack deflection by the ZrO2 crystals and the presence of Zr ions in the residual glass network are prevalent for improving the materials' mechanical properties. Some potential applications, such as bioactive scaffolds, are suggested for these glass-ceramics. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved. (AU)

Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
Beneficiário:Edgar Dutra Zanotto
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs