Mechanical and fracture properties of zircon-mullite composites obtained by direct sintering” , ),

RENDTORFF, N.,; GARRIDO, L.,; AGLIETTI, E

CERAMICS INTERNATIONAL

ELSEVIER SCI LTD

Año: 2009 vol. 35 p. 2907 - 2913

0272-8842

Abstract Refractory materials based on zircon (ZrSiO4) are applied in high temperature applications (1400–1500 8C). They are demonstrated to have an excellent chemical attack resistance, such as corrosion or degradation due to molten glass or metals. On the other hand mullite (3Al2O34) are applied in high temperature applications (1400–1500 8C). They are demonstrated to have an excellent chemical attack resistance, such as corrosion or degradation due to molten glass or metals. On the other hand mullite (3Al2O32O3 ÿ2SiO2) is important both in traditional and advanced ceramics. Although multi-phase ceramic materials were always used, nowadays composite materials have an important industrial and technological development, to enlarge the designing capability of the manufacturer in properties and behaviors. The objective of the present work is to study the influence of the starting composition on the mechanical and fracture properties of zircon–mullite composites obtained by direct sintering of consolidated samples by slip cast of concentrated aqueous suspensions in plaster molds. Zircon–mullite composites using 15–45 wt% mullite were prepared and compared with pure zircon material obtained in the same conditions. Flexural strength (sf), dynamic elastic modulus (E), toughness (KIC) and initiation fracture surface energy (gNBT) were evaluated. The results were explained by microstructure and the XRD analysis. The presence of mullite increased the zircon thermal dissociation. The ZrO2 was a product of this reaction and also influence the mechanical and fracture properties of these materials through several combined mechanisms. Zircon composites prepared with 45 wt% of mullite in the starting powder showed a higher fracture toughness and initiation energy than2) is important both in traditional and advanced ceramics. Although multi-phase ceramic materials were always used, nowadays composite materials have an important industrial and technological development, to enlarge the designing capability of the manufacturer in properties and behaviors. The objective of the present work is to study the influence of the starting composition on the mechanical and fracture properties of zircon–mullite composites obtained by direct sintering of consolidated samples by slip cast of concentrated aqueous suspensions in plaster molds. Zircon–mullite composites using 15–45 wt% mullite were prepared and compared with pure zircon material obtained in the same conditions. Flexural strength (sf), dynamic elastic modulus (E), toughness (KIC) and initiation fracture surface energy (gNBT) were evaluated. The results were explained by microstructure and the XRD analysis. The presence of mullite increased the zircon thermal dissociation. The ZrO2 was a product of this reaction and also influence the mechanical and fracture properties of these materials through several combined mechanisms. Zircon composites prepared with 45 wt% of mullite in the starting powder showed a higher fracture toughness and initiation energy thansf), dynamic elastic modulus (E), toughness (KIC) and initiation fracture surface energy (gNBT) were evaluated. The results were explained by microstructure and the XRD analysis. The presence of mullite increased the zircon thermal dissociation. The ZrO2 was a product of this reaction and also influence the mechanical and fracture properties of these materials through several combined mechanisms. Zircon composites prepared with 45 wt% of mullite in the starting powder showed a higher fracture toughness and initiation energy than2 was a product of this reaction and also influence the mechanical and fracture properties of these materials through several combined mechanisms. Zircon composites prepared with 45 wt% of mullite in the starting powder showed a higher fracture toughness and initiation energy than