surfacecoated

Surfacecoated refers to a material whose surface has been modified by applying a layer of another substance, forming a coating. The coating is usually thin relative to the substrate and aims to provide properties not present in the base material, such as greater hardness, wear resistance, corrosion protection, lower friction, thermal stability, or biocompatibility.

Coatings are applied by deposition techniques including physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplating, thermal spraying, dip coating, and sol-gel processes. They may be ceramic, metallic, polymeric, or composite, with thicknesses from a few nanometers to several micrometers.

Coating materials commonly used include nitrides and carbides for hardness, oxides for protection and insulation, polymers for chemical resistance and low friction, and carbon-based films such as diamond-like carbon. Multilayer or composite coatings can tailor surface properties.

Applications include cutting tools, automotive and aerospace components, medical implants, electronics packaging, and other parts where surface durability is important.

Advantages include increased hardness, reduced wear and friction, improved corrosion and temperature resistance, and longer service life. Limitations involve adhesion and delamination risk, issues from thermal-expansion mismatch, porosity or defects in the coating, cost, and regulatory or environmental considerations.

Characterization uses microscopy and spectroscopy to assess structure and composition, along with measurements of adhesion, roughness, and thickness. Common tests include SEM, XPS, profilometry, and scratch or pull-off tests.

See also surface engineering, coatings, thin films.