Beilby

The term "Beilby layer" refers to a thin, amorphous, highly disordered surface layer formed on metals during mechanical polishing. This layer is thought to be created by the intense heat and pressure generated during the polishing process, causing the surface material to melt, flow, and then rapidly solidify in a disordered, non-crystalline state. The Beilby layer is named after Sir George Beilby, who extensively studied and proposed its existence at the beginning of the 20th century.

While the classical understanding of the Beilby layer involves a molten or near-molten surface, modern theories suggest that the layer might be formed through a combination of plastic deformation, high strain rates, and chemical reactions with the polishing medium. The exact nature and properties of the Beilby layer are still debated, and it is understood that its characteristics can vary significantly depending on the material, polishing technique, and environmental conditions.

The presence of a Beilby layer can have a significant impact on the surface properties of a material, including its reactivity, adhesion, friction, and corrosion resistance. It can also affect the accuracy of surface-sensitive analytical techniques, such as Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). Removing or minimizing the Beilby layer is often a critical step in preparing surfaces for various applications, including microelectronics, catalysis, and biomaterials. Common methods for removing the Beilby layer include chemical etching, electropolishing, and ion milling.