CONICET | Buscador de Institutos y Recursos Humanos

In this study, the high temperature mechanicalbehavior of cordierite porous disks prepared by the starchconsolidation forming method was evaluated. In thismethod, due to the swelling and gelatinization properties ofstarch in aqueous suspension at a temperature between 55and 85 C, the starch granules perform as both consolidator/binder of the green body and pore former at hightemperature. Aqueous suspensions (29.6 vol.%) of a cordieriteprecursor mixture (talc, kaolin, and alumina) withthe addition of potato or cassava starches (11.5 vol.%)were prepared by intensive mechanical mixing, homogenization,and vacuum degasification. Green disks wereformed by thermogelling of the aqueous suspensions at85 C for 4 h followed by additional drying at 50 C for24 h. They were characterized by bulk density and apparentporosity measurements, and microstructural analysis byscanning electron microscopy (SEM) and energy dispersiveX-ray spectroscopy (EDS). Porous cordierite materialswere obtained by calcination at 650 C for 2 h and reaction-sintering at 1330 C for 4 h, employing specific,controlled heating schedules in both treatments. Cordieritedisks were characterized by bulk density and apparentporosity measurements, and microstructural analysis bySEM. Mechanical behavior was evaluated in diametralcompression using a servohydraulic testing machine atroom temperature (RT), 800, 1000, and 1100 C. Apparentstressstrain relationships were obtained from loaddisplacement curves, and mechanical parameters, such asfracture strength (rF), apparent Young modulus (Ea), andyield stress (rY), were determined. Moreover, crack patternswere also evaluated. The obtained results were analyzedin function of the developed microstructures,considering the presence of a silicate glassy phase and acomplex porosity, and the testing temperature.