Corrosion is typically associated with metal, though other forms of alteration may occur, which result in the production of oxides and salts. Though many metals claim to be stainless or corrosion resistant, environmental conditions can result in corrosion, which in turn can result in degradation, failure of machinery, or a source of contamination. Over the years our laboratory has been involved in a wide range of cases focused on both the characterization and identification of corrosion products as well as cases and litigation involving the determination of a corrosion mechanism.
Corrosion products, which are often submitted simply as unknown materials, can be initially examined in situ or as powders collected from the field. A combination of light microscopy, electron microscopy, spectroscopy, elemental analysis (trace and bulk) and x-ray diffraction can be used to identify a specific corrosion product down to its chemical phase (or phases). Traditional sample preparation methods can be used to study corrosion in situ, while more advanced methods such as cross section ion polishing can be used to produce undisturbed preparations of corrosion surfaces. In this way, the stratigraphic development of corrosion and its related phases can be studied.
Microtrace scientists have studied corrosion in a wide variety of products and materials ranging from automotive engines to materials used in food and pharmaceutical applications to specialized alloys used in refinery operations. In some cases, we identified gases (hydrogen) produced and trapped during unexpected corrosion processes.
In many cases, corrosion product residues (or suspected corrosion products) are identified in finished products. In such cases, it is often useful to trace such materials back to their source so as to eliminate their continued occurrence. By identifying the corrosion product and, in some cases, the mechanism of corrosion, we can provide investigative direction to companies looking to trace back a material to a source or possibly a supplier.
In addition to ferrous metals, there are a wide variety of other materials that degrade, breakdown or otherwise alter under specific environmental conditions. These include, concrete, non-ferrous metals (such as copper, uranium oxides, etc.), and glasses. Similar methods can be applied to address questions related to these degradation products.
Antiquities and Metalwork
Over the years we have been asked to investigate corrosion products on various ancient metal objects in an attempt to constrain the origin of a patina. While each case is specific, there have been instances where irregular patinas and corrosion have called into question the authenticity of a piece. Read more about our work on antiquities here.