" PEM 1.6 " Electrolytic Deposit
 
Description of " PEM 1.6 "
Physical characteristics
Production method
Scope of application
Description of " PEM 1.6 " :

Definition :
Electrolytic deposition of tin hardened by formation of surface inter-metal compounds.

Field of application:
Mainly connectors with low insertion force
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Physical characteristics:
Values of electrical contact resistance near to those of bright reflowed tin (EBF).
Low friction factor (friction factor µm ~ 0.23).
High surface hardness (*).
Low insertion forces for a tin coating (*).
Bright appearance; uniform or "mosaic", depending on case.
Reflectivity: this is around 50% when measured as per ISO 2813.
Wetting aptitude: measured as per NFA89400 with an average activated flux; the wetting angles are around 50 degrees.
Ageing: the wetting aptitude is not affected by the "dry heat 16 hours at 155°" test measured under the same conditions (only for brass strips).
Friction corrosion: lower than for EBF.
Coating thicknesses: from 0.8 to 1.2 µm.
Aptitude for brazing: this coating is not considered suitable for soldering as per NFC 20720 (DIN068) with a non-activated flux
Good aptitude for cutting due to the thinness.

(*) This information is drawn from comparative study 1325 undertaken by the Laboratoire Central des Industries Electriques [Central Laboratory of the Electrical Engineering Industries].
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Production method:

 This coating is obtained by an electrolytic process consisting in associating a layer of tin and one or more other layers alloyed to a greater or lesser extent and then diffusing them thermally in order to obtain the hardness of the final coating.

The thermal operation is performed within the electrolytic process, at a temperature higher than the fusion point of tin. The diffusion obtained during fusion of the tin is accompanied by a brightening effect that persists after cooling ("bright reflow finish").

This operation results in a rise in the substrate temperature between 250 and 300° C, for a few seconds only, such that the mechanical characteristics of it are little affected. It is however necessary to undertake systematic verifications certain cases.
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Scope of application:

This process is currently performed on brass. It can be applied to other copper-based materials such as bronzes, and coppers Cu a1 and Cu b1.
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SOFIPEM, Siaugues St Romain 43300 SIAUGUES STE MARIE - FRANCE
Tel: +33 (0)4.71.74.21.09 - Fax: +33 (0)4.71.74.26.57 - Email : contact@sofipem.com