Elaboration and characterization of multiphase composites obtained by reaction sintering of boehmite and zircon

In this work, different composites (zircon–mullite–zirconia, mullite–zircon–zirconia, mullite–zirconia, mullite– zirconia–alumina and alumina–mullite–zirconia) were developed by reaction sintering of boehmite (AlOOH) and zircon (ZrSiO4). Several mixtures were used by varying the boehmite content from 10 to 90 wt. %. All powders were mixed and grounded by ball milling and then pressed in cylindrical form. Finally, the green specimens were sintered under normal conditions for 2 hours at temperatures between 1400 and 1600°C, with a heating rate of 5°C/min. The dilatometric curves reveal several microstructural transformations in these mixtures. The X-rays diffraction spectra revealed factors such as percentage of boehmite and zircon and the sintering temperature lead to the formation of several composites. The presence of the various phases was confirmed by micrographic observations.