Structural changes during crystallization of apatite and wollastonite in the eutectic glass of Ca₃(PO₄)₂‐CaSiO₃system

Abstract

In this study, a bioactive glass of eutectic composition based on Ca3(PO4)2‐CaSiO3 system was prepared and investigated. It was found that by controlling the nucleation and growth of crystals, a glass‐ceramics free from cracks, containing one or two crystalline phases, and of controlled nano‐ to microscale microstructure can be obtained. Heat treatment of the parent glass produces various calcium phosphates (Ca‐deficient apatite and α‐tricalcium phosphate) and calcium silicates (pseudo‐wollastonite and/or wollastonite‐2M) plus amorphous phases. By combining a number of experimental techniques like 31P and 29Si magic angle spinning nuclear magnetic resonance spectroscopy, scanning and transmission electron microscopy, energy‐dispersive X‐ray spectrometry, and Rietveld analysis of X‐ray diffraction patterns, a crystallization model was derived, capable of explaining the observed structural and microstructural changes. The determination of amorphous or crystalline phases enabled to produce time‐temperature‐transformation plots. The structural role on the behavior of these materials and its impact on their in vitro bioactivity are also discussed.

Laser Machining and In Vitro Assessment of Wollastonite-Tricalcium Phosphate Eutectic Glasses and Glass-Ceramics

“…Since the development of Bioeutectic ® ceramic by De Aza et al in 1997 [11], bioactivity and biocompatibility, both in vitro and in vivo, as well as the optical properties of this binary eutectic composite, have been widely studied [14,15,16,17,18,19,20,21,22,23,24,25]. …”

Synthesis of Wollastonite Powders by Combustion Method: Role of Amount of Fuel

“…More attention has been paid on the calcium silicate ceramic materials, particularly wollastonite (CaSiO 3 ), used as a biomaterial for bone regeneration because of its excellent in vitro bioactivity. A lot of authors have studied their ability to induce formation of the hydroxyapatite layer on their surface in vitro conditions when immersed in simulated body fluid (SBF) with ion concentrations, pH, and temperature almost equal to those of human blood plasma [7][8][9][10][11][12][13].…”

A novel Eu3+‐ and self‐activated vanadate phosphor of Ca4La(VO4)3O with oxyvanadate apatite structure

“…It has a framework with a hexagonal space group of P6 3 /m. [2][3][4][5][6] Numerous apatite compounds present rich luminescence colors. The apatite lattices contain two nonequivalent cation sites, i.e., (MII) 4f-site (C 3 point symmetry) with a 9-coordination, and 7-coordinated 6 h-position site (MII) with C s point symmetry.…”

“…1 The interesting apatite structure attracts researchers to develop versatile application such as the well-known biocompatible materials, optical laser hosts, phosphors, and electrolytes for solid oxide fuel cells, etc. [2][3][4][5][6] Numerous apatite compounds present rich luminescence colors. 7 The luminescence and applications of rare-earth (RE) ions activated apatite compounds have been intensively reported.…”