Gold cutlery can be subjected to sputter deposition.
A sputtering machine is usually a small sealed chamber where energetic particles like electrons bombard a source of material that knocks atoms off the surface. These atoms then bounce off the chamber walls, coating a sample object within the chamber. Scanning electron microscopes (SEM), which rely on the electrical conductivity of samples to visualize nanometer-scale features, often rely on this machine to coat biological samples with a thin layer of platinum first for visualization. Other uses for sputtering machine technology include thin-film coating in the deposition process for the semiconductor industry and for peeling off a surface layer of a material to determine its chemical composition.
Expensive jewelry can undergo sputter deposition.
While the machines for which a sputtering machine prepares a sample can be very complex and expensive, sputtering equipment need not be. These machines can be relatively simple devices that work according to established physical principles and often have no moving parts or complex maintenance. They range in size from small desktop devices to large stand-up models.
Physical vapor deposition is a routine method used in the design of sputtering machines. The deposition material is converted to vapor in a low pressure sputtering chamber, usually under partial vacuum. The vapor condenses on the substrate material in the chamber to form a thin film. This film may only be several layers of atoms or molecules thick and will thicken in direct proportion to the duration of the sputtering process. Other factors in thin film thickness include the mass of each material involved and the energy level of the coating particles, which can charge anywhere from tens of electron volts to thousands.
Charged atoms known as ions are also used by a sputtering machine in a process known as potential sputtering. The sprayed material receives an ionic charge which it loses when it hits the target surface. Related to this process is reactive ion corrosion (RIE), which uses naturally occurring ionic materials in secondary ion mass spectrometry (SIMS) research to analyze the presence of trace elements in materials. SIMS static processing will fire at such a fine rate that only a tenth of an atomic monolayer will be removed from the target surface. Therefore, it is another useful tool in nanotechnology research as is the sputtering machine for SEM.
Other uses include coating flat glass, acrylic and other plastics, as well as ceramics and non-silicon crystals. They can also be used as a very fine method of cleaning and polishing delicate components. Expensive jewelry and cutlery, such as gold cutlery, can also be sputtered, as can specialized gold and aluminum foil.