Authors: Jakub Jaroszewicz Wout De Nolf Koen Janssens Andrzej Michalski Gerald Falkenberg
Publish Date: 2008/05/06
Volume: 391, Issue: 4, Pages: 1129-1133
Abstract
Design and processing of new materials with improved hightemperature properties is one of the most challenging tasks of modern engineering Among such materials nonoxidic ceramics hold an important place When optimizing the synthesis conditions of these new materials in an largely empirical manner the use of analytical methods that can fully document the resulting phase compositions is of great importance In this paper we demonstrate the advantages of using combined microbeam Xray diffraction and Xray fluorescence over conventional Xray diffraction as the characterization method in the specific case of Ti–B–C ceramics Ceramic samples were synthesized by the pulse plasma method starting from highpurity powders of titanium boron graphite and nickel Different mixtures were heated in a pulsed fashion and sintered by combustion synthesis at various temperatures and time durations as is the case during empirical optimization of a synthesis procedure Conventional Xray diffraction showed the presence of two phases at the end of the sintering process TiB2 and TiC irrespective of the conditions employed Scanning μXRF/μXRD on the other hand allowed one to detect and visualize the distribution of additional phases present in the sintering products during which a dependence on sintering conditions was apparent The μXRD results showed that three phases TiB2 TiC and TiB instead of two were present in samples sintered during a short time interval The addition of metallic Ni to the initial mixture as a sintering facilitator resulted in the formation of a Ni3B phase All phases proved to have strongly heterogeneous distributions above the 15μm level with the presence of TiB2 anticorrelated to that of TiC and TiB emphasizing the necessity of the use of laterally resolved methods of characterizationThis research was supported by the Interuniversity Attraction Poles Programme Belgian Science Policy IUAP VI/16 The text also presents results of GOA “Atom” Research Fund University of Antwerp Belgium and of FWO Brussels Belgium projects no G017703 G010304 and G068906
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