The creep behavior of solid ceramics is strongly affected by the microstructure. Fundamentally, there are three microstructural features which influence the creep behavior: the mineral content, the flux content and the apparent porosity. Additionally, the creep of cellular ceramics also depends on their macrostructure constituted by a tridimensional array of struts. Therefore, the creep analysis of these materials should consist of two stages. Firstly, identification of the macrostructure deformation mode and secondly, determination of the stress exponent (n) and the activation energy (Q). In this work the analysis of creep under compression of 0.034; 0.051 and 0.068 MPa at 1500, 1550 and 1600 ºC in air was carried out in Al2O3 filters with 10 ppi. The results suggested that buckling of struts is an important factor to be considered, since it contributes to increase the deformation rate and, therefore, the values of n and Q. Besides the struts deformation mode, the way that the creep test is carried out (with or without load change) will influence the determination of n and Q values.
ceramic filters; creep; alumina
