Phase Evolution, Microstructure, and Mechanical Properties of Alumina–Mullite–Zirconia Composites Prepared by Iranian Andalusite

Abstract

This paper investigates the effects of Iranian andalusite and short milling times on alumina–mullite–zirconia composites. Andalusite powder was added at 0, 2.5, 5, and 10 wt% to an alumina–zircon mixture and the raw materials were milled for 1 or 3 h. The sintering of samples was carried out at the temperatures of 1550°C, 1600°C, and 1650°C for 3 h. Microstructural changes, phase composition, physical properties, and mechanical strength of the sintered composites were characterized by scanning electron microscopy, X‐ray diffraction, density, and strength measurement tests. Results show that andalusite promoted the decomposition of zircon and accelerated the reaction sintering of alumina–zircon, which leads to the formation of much more mullite phase and improvements to the composites’ thermal shock resistance up to about 50%.

Synthesis of an innovative zirconia-mullite raw material sintered from andalusite and zircon precursors and an evaluation of its corrosion and thermal shock performance

“…Majidian et al [10] had studied the phase evolution and the microstructures of aluminamullite-zirconia composites mixed using Iranian andalusite and have shown similar results.…”

“…It has been found that andalusite powder can reduce the decomposition temperature of zircon to 1600 °C [10,28] and accelerate the sintering of alumina-zircon, which leads to an increase of the mullite amount and improves the thermal shock resistance of the alumina-mullitezirconia composite.…”

“…Andalusite is a well-known alumina-silicate mineral employed in the refractory industry to provide high thermal shock resistance and strong mechanical properties. Majidian et al [10] determined that the addition of andalusite in an alumina-mullite-zirconia composite improves properties such as thermal shock resistance.…”

Development of AMZ composites via mutual attraction of particles in wet processing

“…However, mullite formation and complication of reaction sintering demand high temperatures and longer times. To achieve this, some approaches such as incorporation of additives, 6,8,10,11 use of mineral industrial raw materials, 12 mechanical milling, 1,5,13 and microwave sintering 5,14 have been studied to promote the reaction sintering process and reduce the sintering temperature as well as energy consumption.…”