No silver not low silver

Circuit World

ISSN: 0305-6120

Article publication date: 22 August 2008



(2008), "No silver not low silver", Circuit World, Vol. 34 No. 3.



Emerald Group Publishing Limited

Copyright © 2008, Emerald Group Publishing Limited

No silver not low silver

Article Type: New products From: Circuit World, Volume 34, Issue 3

Many lead free solders for assembly or on-board solderability preservation contain silver. For every 1 per cent of silver used in these alloys the material cost of the solder increases by over 80 per cent. As silver prices soar, so the cost of these solders will continue to increase. The cost of silver has virtually doubled in the past two years and some prophets forecast a further 50 per cent increase in the foreseeable future so perhaps now is the time to consider “No Silver” rather than “Low Silver” solder.

A modified tin copper alloy, Fenix 100, available from JE Debens, is reported to offer outstanding performance without any silver content at all, making it an extremely economical alternative to the widely used SAC alloys.

Previous attempts to formulate without silver have resulted in solders with higher melting points that could potentially cause damage to both board finish and components. Fenix 100 has a modified structure that makes the melted alloy more fluid so that it solders at lower temperatures. The recommended wave soldering temperature of 260°C is the same as that recommended for SAC 305 alloys.

Fenix 100’s modification treatment also inhibits the copper dissolution suffered by many other lead-free alloys, a copper affinity of tin that not only reduces pot life but also damages fine copper tracks and wires in the circuitry.

The surface appearance of most lead-free solders whether in a solder joint or a solder levelled pad is duller than that achieved previously with tin-lead alloys. The modification treatment undergone by Fenix 100 produces shinier joints and pads and significantly less surface cracking than many other lead-free alloys.

It is also said that using Fenix 100 reduces the levels of corrosive attack on the steels used for solder pots, pumps and wave formers, making expensive upgrading of wave solder and solder levelling machines unnecessary.

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