ABSTRACT

The corrosion of a polycrystalline ceramic by vapor attack can be very serious, much more so than attack by either liquids or solids. One of the most important material properties related to vapor attack is that of porosity or permeability. If the vapor can penetrate into the material, the surface area exposed to attack is greatly increased and corrosion proceeds rapidly. It is the total surface area exposed to attack that is important. Thus not only is the volume of porosity important, but the pore size distribution is also important. See Chapter 12 for a discussion on porosity determination.