Ceramic matrix composite corrosion models

This paper discusses physical and empirical models for the description of corrosion processes. Physical strict models are advantageous for simple ceramics and simple composites. In additive-containing ceramics and composites with such matrices, the transport properties will vary with time; in these cases simple physical models alone are not adequate. The use of an empirical equation of the form x=klt+k′pt+kloglog⁡(t), fitted by simple multiple linear regression, is capable to describe many versions of corrosion processes, if kl is allowed to become negative or positive (x: scale thickness or specific mass change, t: time). The equation is recommended for complex cases, but the variability of the corrosion function makes it often necessary to have more than one parameter of evaluation of the material to deduce the most important engineering parameter, penetration depths.