CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
artículos
Título:
Mullite–zirconia–zircon composites: Properties andthermal shock resistance
Autor/es:
N. RENDTORFF; L. GARRIDO; E. AGLIETTI
Revista:
CERAMICS INTERNATIONAL
Editorial:
ELSEVIER SCI LTD
Referencias:
Año: 2009 vol. 35 p. 779 - 786
ISSN:
0272-8842
Resumen:
In the refractory field mullite and zirconia are the basis of materials used in the glass industry or when high chemical stability and corrosion resistance are necessary. In this work various mullite–zirconia/zircon compositions were investigated to improve the thermal shock (TS) resistance of dense composites produced by slip casting and sintering at 1600 8C. Zircon (SiZrO4) acts as bonding phase and its thermal decomposition adds zirconia and silica to the material. Resultant composites were characterized by density and dilatometric measurements, XRD and SEM techniques. TS behavior was tested by quenching in water with quenching temperature differentials DT from 400 to 1200 8C. The degree of damage after the TS was experimentally evaluated through the variation of the elastic modulus E which is measured by the excitation technique. The severity of the TS test and the effect of the number of thermal cycles on E for each DT employed were determined. The tested materials retained their original mechanical properties for temperatures below a critical temperature DTc near 600 8C. Materials quenched from DTof 1000 8C showed as much as 30% reduction in E indicating the important microstructure damage. The TS resistance improved with increasing zircon addition to 35 wt% in agreement with the behavior predicted from R parameter for crack initiation