The development of ceramic foam material began in the 1980s. It is a kind of porous material with high temperature characteristics. The pore size varies from millimeter to micron, the porosity is between 20% and 95%, and the operating temperature is between room temperature and 1600°C.
Foam ceramics can generally be divided into two categories, namely open-cell ( mesh ) ceramic materials and closed-cell ceramic materials, depending on whether each cavity has a solid wall. If the solid forming the foam is only contained in the pore edge, it is called open-cell ceramic material, and the pores are interconnected ; if there is a solid wall, the foam is called a closed-cell ceramic material, where the cavities are separated from each other by a continuous ceramic matrix. However, most of the foam ceramics have both open pores and a small amount of closed pores. Generally speaking, the pore diameter is less than 2nm for microporous materials ; mesoporous materials with pores between 2 ~ 50nm ; macroporous materials with pores above 50 nm.