Silvering

The silvering processo for decorative purposes

The silvering process is widely used, as well as for decorative purposes, in many applications in the electronic, space, defense, microelectronics and telecommunications sectors in general.
The use of silver is particularly indicated in high-frequency transmissions (for example waveguides), thanks to its high conductivity which minimizes the current leakage offering an excellent transmission of the electrical signal, from the RF to the HF the order of tens of GHz.
The silver is sensitive to the presence of sulfides in the air and tends to blacken over time (a phenomenon which is known as "tarnishing"; that, in addition to alter the aesthetic aspect, increases the contact resistance: The "tarnishing"; phenomenon can be inhibited by a final passivation which largely exceeds the test QQ-S-365, it does not affect either the weldability or the electrical properties and conforms to the European RoHS directive.

Power filters in coaxial cavity for spatial applications, UHF band - Thales Alenia Space Italy

High Power coaxial cavity filters for space applications (UHF) – Thales Alenia Space Italy

• When the corrosion resistance is an important requirement it is necessary to apply a substrate of electrolytic nickel or chemical nickel (preferable for the greater uniformity of thickness), with a thickness of 10 microns minimum.
• The silver on copper and its alloys can be deposited directly, without sublayers, as long as the treated articles must not be soldered (brazed) or have an operating temperature exceeding 149 ° C (there is a loss of adhesion due to the formation of a light intermetallic copper-silver layer); otherwise you need a nickel barrier layer of the order of 3-5 microns.
• On aluminum and its alloys the ideal substrate is the chemical nickel.
• On ferrous alloys, zinc and its alloys must be provided a first layer of copper followed by nickel.

Parts for telecommunications equipment - silver plating on brass base

Telecommunications sector - Tuning silver