Beneficial Aspects of the Environmental Instability of Materials

Abstract

The environmental degradation of materials poses a serious limitation in the utility of engineering materials. The corrosion of metals, for example, has been estimated to represent a 4–5% decrease in the Gross National Product each year. To this, add losses involved in the replacement or restoration of ceramic structures such as buildings and transportation systems, i.e., the “infrastructure,” and the result is a significant sacrifice of economic strength.Most of us are familiar with the consequences of exposing materials to environments in which the materials are chemically unstable and convert into substances that are unable to perform the function for which the original material was selected. The corrosion of metals into soluble or insoluble oxidation reaction products, chain scission or molecular mutation in polymers, even hydrolysis and leaching of silicious ceramic compounds represent behavior which ultimately limits the service applications of most engineering materials. For example, aluminum and its alloys are unsuitable for use in environments where oxide formation rates are high enough to represent a problem with respect to useful service life.