Mechanical properties and microstructural evolution of alumina–zirconia nanocomposites by microwave sintering

Abstract

Microwave sintering has emerged in recent years as a novel method for sintering a variety of materials that have shown significant advantages against conventional sintering procedures. This work involved an investigation of microwave hybrid fast firing of alumina-zirconia nanocomposites using commercial alumina powder and monoclinic nanometric zirconia. The suspensions were prepared separately in order to obtain 5, 10 and 15 vol.% of ZrO 2 in the alumina matrix. The samples were sintered in a 2 monomode microwave furnace at 2.45 GHz in air at different temperatures in the range 1200-1400 ºC with 10 min of dwelling time and 200 ºC/min of heating rate. The effect of sintering temperature in densification, mechanical properties and microstructure behaviour of the composites was investigated.Higher density, hardness and Young's modulus, excellent fracture toughness properties and homogeneous microstructure were achieved by microwave sintering in comparison to conventional heating. Microstructure analysis showed that the alumina grains had not grown significantly, indicating that the zirconia particles provided a hindering effect on the grain growth of alumina.

Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

“…The density of composite decreased and the open porosity of the ceramic materials grew with increasing amount of Al 2 O 3 . Several studies have manufactured dense ceramics while maintaining a small grain size; most of them used optimized sintering strategies or advanced sintering techniques [11,26,31]. Numerous analyses of the mechanical properties of Al 2 O 3 –ZrO 2 composite systems have also been reported upon [32,33,34,35,36,37], and a wide range of results have been presented.…”

A study of the influence of TiO2 addition in Al2O3 coatings sprayed by suspension plasma spray

“…Nowadays, a bulk ceramic piece with a nanostructured microstructure can be produced by sintering nano-sized powders via fast routes (to prevent grain growth) such as microwave furnaces [7,8] or Spark Plasma Sintering techniques [9,10].…”

High thermal stability of microwave sintered low-εr β-eucryptite materials

“…Microwave radiation of ceramic components has recently gained new relevance in the fields of sintering and joining ceramics due to its advantages over conventional heating techniques. [14][15][16][17] Benavente and coworkers [18] developed microwave equipment specially designed to fabricate ceramic materials of lithium aluminosilicate (LAS) in solid state with high density and have high mechanical properties (hardness and Young's modulus). The important characteristics associated with microwave sintering of ceramic materials are rapid and uniform volumetric heating, improved production rate, enhanced densification and inhibition of grain growth.…”