Poeton offer a specialist silver plating service from their 'One Stop Shop' facility at the UK Cardiff site. The main applications are in aerospace and defence, for anti-bonding and anti-fretting, as well as for electronic parts.
Silver gives excellent anti-fretting properties as well as providing a corrosion resistant surface. It also has high electrical conductivity, and is FDA compliant (previously ‘FDA approved’) for applications in the food and medical industries.
The Silver bath is 1200mm x 600mm x 600mm; holding 400 litres, maximum working depth of 550mm. We can handle large parts up to 50 kg in weight.
Thicknesses are typically between 10 and 25 microns. The bath composition contains a small amount of brightener additive (to give a slight sheen for electrical contact purposes) which prevents effective deposit thicknesses in excess of 50 microns.
Applications that dominate are anti-binding and anti-fretting on stainless steel for aerospace components, including splines and couplings. Electrical contacts for electronics are also common, not just on miscellaneous small connector pieces, but on large copper slabs for pylon and power station construction.
Apticote 600 silver plate is resistant to many organic acids, as well as sodium and potassium hydroxide. When sulphur is a hazard, special anti-tarnishing treatments can be applied to greatly increase the protection. Silver is not recommended for use with inorganic acids; nitric, hydrochloric, sulphuric, etc.
Anti-galling and anti-fretting
Apticote 600 silver has a low coefficient of friction, making it ideal as an anti-galling (cross-transfer of metal, and subsequent adhesion and seizure). Stainless steel bolts and screw threads, and parts made in titanium, can all be protected.
Because of its oxidation resistance, Apticote 600 silver plate is ideal in fretting situations (splines, couplings, housings), where oxidation, and abrasion by the oxide debris is eliminated.
The high conductivity makes silver plate ideal for heavy duty electrical contacts, including circuit breakers and slip-rings. However, its susceptibility to sulphide attack precludes use in low force, low load contacts, unless overlaid with gold or rhodium. (In heavy duty applications, any surface sulphide film is easily broken through.)
Poeton Apticote 600 is a fully bright, even coating, reflecting 90 to 95% in the visible spectrum, after polishing.
Poeton work to a range of BS, Def.Stan and MIL specs, covering aspects of the plating such as pre-treatment (coating adhesion), thickness (including the requirements for threaded parts), purity, any pre or post treatment, test methods and inspection. Please consult Poeton for details.
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