Comportamiento mecánico a alta temperatura de materiales cerámicos porosos a base de cordierita evaluado en flexión en tres puntos

S.E. GASS; M.L. SANDOVAL; M.H. TALOU; A.G. TOMBA MARTINEZ; M.A. CAMERUCCI; E. GREGOROVÁ; W. PABST

Santa Fe

Congreso; Congreso Internacional de Metalurgia y Materiales SAM-CONAMET/IBEROMAT/MATERIA 2014; 2014

Cordierite based ceramics are an important segment of the present ceramic industry. In the last years, cordierite based porous ceramics have received great attention as light structural materials, thermal insulting and catalyst supports, among others. For these applications, a combination of high porosity and low weight of the component are required, together with mechanical stability even at high temperatures which might prevail in use. The combination of these requirements is a challenge due to the compromise existing among them. In this work, materials prepared from two mixes precursor of cordierite based on kaolin, talc and alumina by thermal consolidation (80°C, 4 h) of stable aqueous suspensions mix-starch were evaluated. Two different native starches, potato and corn, were employed. The starch gel, which acted as binder in the green body, generates the pores when it was eliminated during a further thermal treatment (650°C, 2 h). The transformation of the raw materials in cordierite was carried out by reaction-sintering at 1330°C, 4h. Cylindrical bars of 35-50 mm in length and 3.5-4.0 mm in diameter were prepared using this method, and then, they were mechanically evaluated from room temperature to 1100°C using 3-point bending. A servohydraulic testing machine INSTRON 8501, a SiC fixture (span: 30 mm) and displacement control (0.1 mm/min) were used for the mechanical testing. The difference observed in the behavior and the mechanical parameters (Young modulus and mechanical resistance) were related with the characteristics of raw materials and the composition, texture and microstructure developed in the final materials, especially porosity and the presence of glassy phase.