Publication Cover
Advances in Applied Ceramics
Structural, Functional and Bioceramics
Volume 110, 2011 - Issue 3: Cement and Concrete Research
173
Views
16
CrossRef citations to date
0
Altmetric
Original Article

Phase transformation and sintering behaviour of mullite and mullite–zirconia composite materials

, , , , &
Pages 175-180 | Received 07 Nov 2008, Accepted 15 Jan 2011, Published online: 22 Nov 2013
 

Abstract

Abstract

Mullite is one of the most promising engineering materials for applications at elevated temperatures, but has poor mechanical properties at ambient temperature; therefore, it is usually reinforced with particles, fibres or whiskers to improve its properties. Among particles added to mullite are ZrO2 particles which improve its fracture toughness through the well known process of phase transformation from tetragonal to monoclinic in zirconia particles. The aim of the present work is to explore the utilisation of Algerian kaolin, α-Al2O3 and ZrO2 to synthesise mullite–ZrO2 composites through reaction sintering and investigate phase transformation and sintering behaviour of the composites. The raw materials were mixed through planetary ball milling followed by attrition milling. Compacted samples were sintered at temperatures between 1100 and 1600°C for 2 h. The bulk density was measured by the water immersion method. X-ray diffraction (Rietveld method) was used to characterise phases present in the sintered samples. It was found that the zirconia phase retained its tetragonal structure with the addition of up to 16% zirconia. The formation of primary mullite in all samples was complete at 1250°C. The cristobalite started to form at 1150°C, and disappeared at 1300°C in the samples of mullite, and at 1250°C when ZrO2 was added. The zircon compound ZrSiO4 started to form at 1250°C and completely disappeared at 1400°C. The increase in ZrO2 ratio promoted the formation of grains with spherical shape.

The first author is grateful to the technical support from Laboratoire de Physique et Chimie des Matériaux, Université de M’sila, Algeria, and the Department of Special Ceramics, ENSM, France. Also, the corresponding author (Dr N. Saheb) would like to acknowledge the support from King Fahd University of Petroleum and Minerals, Saudi Arabia.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.