Characterization of surfaces by GDOES

The properties of materials depend increasingly on their surface composition. Over the last thirty years, industry has been developing coatings and treatments that use mechanical, physical, chemical or electrochemical means to modify the nature, composition, structure or state of stress of a material's surface, without altering its core characteristics. Surface treatments therefore make it possible to improve the surface properties of a material to give products greater added value by making them more resistant to corrosion, oxidation, wear and friction, and more efficient thermally, electrically by improving their weldability or simply their appearance, etc. For example, by protecting carbon steel with a zinc coating, passivation and a paint system, it can be given corrosion resistance while retaining excellent mechanical properties, as is the case for automotive sheet metal, for example.

The development of such treatments has necessitated the introduction of study and control tools to ensure reliable, reproducible products.

With the rapid expansion of the surface treatment industry, the analysis and characterization of surfaces is now a necessity in many fields: corrosion, oxidation, passivation, catalysis, wear, friction, lubrication, diffusion, adsorption, adhesion, thermal and electrical conductivity, photovoltaics, etc. Depending on the problem studied and the properties concerned, the definition of surface can vary widely. Depending on the problem studied and the properties concerned, the definition of the term surface can vary widely, from a strict monolayer to layers reaching several tens of micrometers or more, from 50 to 100 µm thick of alumina (Al ₂ O ₃ ) for example after hard anodizing treatment on an aluminum part.

There is a wide variety of analysis methods available, some of which are mainly used in university research or technical centers. However, as a result of numerous developments, the range of equipment available has expanded considerably, and now depends on the degree of sophistication and progress of the technique, as well as on the added value of the product being analyzed. However, if we exclude the microelectronics field, few methods are suited to the inspection of industrial surfaces, as long as rapid information is required on a large number of elements and for highly variable layer thicknesses, which is often the case after treatments or coatings. Furthermore, the quality of the samples does not always allow for high vacuum (porosity, high roughness, presence of organic residues, etc.).

Thanks to its ease of use, speed, ability to measure all elements, and wide range of applications, glow discharge...