Multiphase composites obtained by sintering reaction of boehmite and zircon part I: Development and microstructural characterization

Abstract

In this work, different composites (zircon-mullite, zirconia-mullite-zirconia, mullite-zirconia and alumina-zirconia-mullite) were developed by reactive sintering of a powder mixture of boehmite (AlOOH)) and zircon (ZrSiO)4. These powder mixtures were mixed and ground by ball milling and then pressed in cylindrical form. Finally, the green specimens were sintered in air during 2 hours between 1400°C and 1600°C, with a heating and cooling rate of 5°C/min. The dilatometric curves show that there are several microstructural transformations in these mixtures. X-rays diffraction spectra showed formation of several composites depending on the initial conditions (% of boehmite and zircon and sintering temperature). The micrographic observations of the samples confirmed the presence of various phases.

Keywords

• Multiphase composites
• Reactive sintering
• Development
• Alumina
• Zircon
• Mullite
• Zirconia.