ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
This document describes and discusses the non-isothermal devitrification process of thewollastonite-tricalcium phosphate (W-TCP) eutectic glass. This eutectic glass has been studied insitu, from room temperature up to 1375 ºC, by Neutron Diffractometry (ND) in vacuum. The dataobtained were complemented and compared with those performed on ambient atmosphere byDifferential Thermal Analysis (DTA) and with those of samples fired in air, at selectedtemperatures, and then cooled down and subsequently studied by laboratory X-ray PowderDiffraction (LXRD) and Field Emission Scanning Electron Microscopy (FE-SEM) fitted withEnergy X-Ray Dispersive Spectroscopy (EDS). Selected samples have been investigated byquantitative full-phase analysis (including the amorphous content) using the Rietveld method. Theexperimental evidence indicates that the devitrification of W-TCP eutectic glass, begins at ~870ºC,with the crystallization of a Ca-deficient apatite phase (Ca9.92(P5.85O23.54)(OH)2.03 (H2O)2.194)followed by wollastonite-2M (-CaSiO3) crystallization at 1006ºC. At 1375ºC the bio glassceramicis comprised of quasi-rounded colonies formed by a homogeneous mixture ofpseudowollastonite (-CaSiO3) and -tricalcium phosphate (-Ca3(PO4)2). This microstructurecorresponds to irregular eutectic structures and is similar to that of Bioeutectic® W-TCP materialobtained previously, via controlled slow solidification of the eutectic composition, by some of thepresent authors. It has also been found that from the eutectic composition of the wollastonite –tricalcium phosphate binary system is possible to obtain a wide range of bio glass-ceramics throughappropriate design of thermal treatments
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/57/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.396-398.127.pdf
