AFM Analysis if Metals

Atomic Force Microscopy is commonly used to examine the surface structure of metals. Whether it’s coatings, contamination, or corrosion, the Atomic Force Microscope provides a tool for better understanding.

Illumination/slope mode images of height data on aluminum foil purchased at retail. The linear marks are rolling marks from the manufacture of the foil. The smaller bumps are surface residue, probably from lubricant used in the manufacturing process.

Coatings

Metals are coated to control friction, to protect the metal from the environment, to protect the environment from the metal, and for other purposes.  The performance of the coating depends on the structure, particularly when the coating is a thin film where irregularities can easily become perforations.

Coating on the interior of an aluminum beverage can. The coating serves to prevent the acidic beverage from etching the can and from adding aluminum to the beverage. The left pain shows height data, with bright/yellow areas being high and dark/red being low. The right pane is phase data and maps different material characteristics of the coating.

Finish

The surface finish of a part can be a vital factor in how well it works.  The Atomic Force Microscope, by making a three-dimensional map of the surface, allows detailed examination of the surface finish.  Both quantitative analysis of surface roughness and bearing plots can be performed.  The AFM can measure surface roughness over a very wide dynamic range:  from Ra = 0.03 nm to 500 nm

 

Corrosion

Many metals are used in harsh environments where corrosion is a concern.  Understanding the process of corrosion allows engineers to develop ways to better control corrosion allowing for better part life and lower life-cycle costs.

Corrosion on carbon steel after brief exposure to dry steam. The corrosion begins as plaques around bumps and hollows of the material.
Corrosion on carbon steel after longer exposure to dry steam. The plaques have become more numerous and have grown to cover most of the surface.

These are just a few of the ways Atomic Force Microscopy can help engineers in the metals industry.