Numerical simulation on effects of pore characteristics on strength in porous ceramics

Abstract

It is well known that porous ceramics have higher heat-resistance and larger specific surface area. So, porous ceramics are suitable for applications to functional components such as refractory, filters and catalysts. Even if applications of porous ceramics are functional, their strength properties should be adequately evaluated to guarantee long-term durability with satisfying the required functions. In previous studies (Yoshida et al., 2006) (Fujii et al., 2007), strength properties of porous ceramics were discussed by considering bulk porosity only. It has been recognized that the strength of porous ceramics with higher bulk porosity becomes lower in general. It should be noted, however, that not only bulk porosity but also spatial and size distributions of pores affect strength properties of porous ceramics; e.g., there is possibility that the strength of a porous ceramic material with higher bulk porosity increases by decreasing sizes of individual pores within the material. Actually, such an irregular behavior was confirmed in a porous alumina (Miyazaki and Hoshide, 2018). From a viewpoint of material design, it is desired that the strength properties can be predicted for pore characteristics resulted from a specified processing of porous ceramics. The strength properties are usually obtained by experiments. However, if the strength properties are determined experimentally, various ceramic materials with different porosities should be produced and a lot of specimens for respective materials should be prepared because very large scatter of strength is well-known in ceramics. Consequently, it is convenient that virtual porous ceramics with various porosities can be made and strength