Influence of Mg-doping, calcium pyrophosphate impurities and cooling rate on the allotropic alpha <->beta-tricalcium phosphate phase transformations
authors Torres, PMC; Abrantes, JCC; Kaushal, A; Pina, S; Dobelin, N; Bohner, M; Ferreira, JMF
nationality International
journal JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
author keywords Tricalcium phosphate; Calcium pyrophosphate; Mg substitution; Phase transition; Thermal stability
keywords BETA-TRICALCIUM PHOSPHATE; NEUTRON POWDER DIFFRACTION; X-RAY-DIFFRACTION; ALPHA-TRICALCIUM; SETTING REACTION; HIGH-TEMPERATURE; BONE; SYSTEM; SUBSTITUTION; CEMENT
abstract Alpha and beta-tricalcium phosphates are allotropic phases which play a very important role as bone graft substitutes, namely in calcium phosphate cements. Despite extensive research efforts, contradictory reports exist on the importance of quenching for maintaining alpha-TCP purity. The role of calcium pyrophosphate impurities derived from a certain calcium-deficiency, hydroxyapatite impurities derived from calcium excess, and various ionic substitutions on thermal stability of these phases was not yet fully disclosed. The present work reports on the kinetics of alpha <->beta-TCP phase transformations of calcium-deficient TCP powders with different Mg-doping extents (0-5 mol%) prepared by precipitation. Mg clearly enhanced the thermal stability of beta-TCP. The effect of cooling rate was more complex and interdependent on the Mg content and the heat treatment schedule. High alpha-TCP contents were retained upon cooling at 5 degrees C min(-1) for Mg <= 1 mol% or upon quenching from 1550 degrees C for Mg contents <= 2 mol%. (C) 2015 Elsevier Ltd. All rights reserved.
publisher ELSEVIER SCI LTD
issn 0955-2219
year published 2016
volume 36
issue 3
beginning page 817
ending page 827
digital object identifier (doi) 10.1016/j.jeurceramsoc.2015.09.037
web of science category Materials Science, Ceramics
subject category Materials Science
unique article identifier WOS:000367407900051
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