Talk:Whisker (metallurgy)

Tin whiskers

Material from Tin whisker contributed by 68.163.158.93 merged — PhilHibbs | talk 10:51, 10 Jan 2005 (UTC)

Slashdot recently ran an article on "tin whiskers", which explains the flurry of activity on this date. — PhilHibbs | talk 11:18, 10 Jan 2005 (UTC)

delete this sentence, it is wrong and not needed

Unlike zinc whiskers, tin whiskers don't have to be airborne to damage equipment, as they are typically already growing in an environment where they can produce short circuits.

Implies that zinc whiskers have to be airborne to cause short circuits. This is wrong; while zinc whiskers may certainly move around via air currents, they cause short circuits only when embedded in electrical circuits. Also, air currents aren't the only way that zinc whiskers move around. I'm really surprised that you (Christopher Thomas) forced this issue to the talk page. It's a very simple point. The article is more clear without this sentence, it is not needed and should be omitted for clarity. --Duk 16:46, 6 January 2006 (UTC)

I've "forced the issue to the talk page" because you appear to be the only editor who's touched the article who feels that the original statement was out of place. Zinc whiskers appear on zinc-coated surfaces (usually zinc electroplated ones, as dip-galvanized surfaces tend not to form whiskers). These are things like equipment cases, and especially the undercoatings of the floor tiles uesd in data centres. If left undisturbed, zinc whiskers from these surfaces don't do anything, as they're nowhere near traces that could be shorted. Damage typically occurs when the whisker-bearing items are disturbed, sending whiskers into the air to settle on nearby electronics. This is especially catastrophic when doing things like data centre renovations, which send vast numbers of whiskers from the floor tiles through the data centre's ventilation system. The links from the article provide ample references for this.

Tin whiskers, on the other hand, grow from surfaces coated with tin alloys - including many solders, and (as noted in the article) alloys used for component pins. Solder-coated traces on printed circuit boards _are_ close enough together for whiskers grown in-situ to cause shorts. Similarly, cases like the crystal case pictured in the article have little clearance between the pins and the casing shell, which whiskers can short across. This too is documented in the article and the article's references.

Claiming that the sentence, either in its original or modified forms, is "wrong" is extremely odd, given these points of context. If you feel it should be _phrased_ differently, by all means suggest alternate phrasings, but deleting it when it accurately describes typical damage scenarios is out of line. --Christopher Thomas 19:12, 6 January 2006 (UTC)

So Mr. Thomas you are essentially conceding that the sentence IS wrong if not elaborated upon as it is only true within the context of a particular set of design parameters where these metals are used, and it is not the case that the metals themselves inherently have these properties. Thus, the sentence should be clarified or removed as it is not factually accurate as stated except in particular cases and in fact you cannot conclude there would never be a case where there was no zinc present in the vicinity of electrical circuits, especially in this day and age of trying to miniaturize everything. — Preceding unsigned comment added by 74.136.254.181 (talk) 18:18, 23 August 2012 (UTC)

Ice spikes

Are they related in any way to Ice Spikes? --82.36.20.32 00:20, 20 March 2006 (UTC)

From what I understand, no, not really. Ice spikes are non-crystalline projections caused by mechanical stresses and failure during the freezing process. Tin and zinc whiskers seem to be single-crystal growths forming after the freezing process by diffusion at room temperature. However, the impression I get from the articles is that metal whisker growth is poorly understood, so it's possible that I'm wrong about some of the details. --Christopher Thomas 18:52, 14 April 2006 (UTC)

Germanium

Germanium whiskers may be worth noting here too. --Trɔpʏliʊm • blah 15:23, 3 September 2009 (UTC)

Effect of circuit potting and spray-coating?

Does potting a circuit in wax or polymer reduce or prevent whisker growth from the circuit traces? Or can the crystalline growths "burrow" through potting?

In the case of raised floors releasing airborne whisker fragments, even a simple spray coating of polyurethane on circuit boards to insulate them would prevent shorting due to Zinc whiskers. The fibers might blow into equipment but would rest on top of the insulating polyurethane layer.

Alternately, the underside of metal raised-floor tiles might be spray coated with poly or simply covered with adhesive plastic to prevent whisker separation from the tile. They may grow under the plastic but cannot become airborne.

Potting and coating does make circuit repair and modification much more difficult, but usually with manufactured devices it tends to be more common for a design to be frozen in place permanently.

DMahalko (talk) 11:06, 16 September 2009 (UTC)

Mitigation and limits

http://nepp.nasa.gov/WHISKER/photos/pom/2004april.htm seems to suggest that even lead can not prevent but only mitigate the problem. Conversely, galvanic soldering seems to make things much worse and hot dip soldering can largely prevent whiskers even without lead. This article reads much differently than the German one which suggests to me that at least one of them is politically charged and playing the problem up/down. --Mudd1 (talk) 22:02, 10 July 2012 (UTC)

This is not necessarily the case, rather that in addition to leaded solder, also the component leads themselves should have some lead instead of only tin plating. The picture merely shows the area on the component lead that was not coated with solder. — Preceding unsigned comment added by 74.136.254.181 (talk) 18:32, 23 August 2012 (UTC)

Possibly inaccurate photo

The photo shown in the article appears to be dendrites due to their branching structure similar to the copper ones shown here: http://nepp.nasa.gov/whisker/dendrite/index.html and not whiskers as shown here: http://nepp.nasa.gov/whisker/background/index.htm --108.72.214.22 (talk) 05:16, 14 October 2012 (UTC)

New research

I don't have time to "do it right" but recent research needs to be incorporated into the article, preferably by someone who knows something about the phenomenon. Some useful links: USC doctoral student unravels 'tin whisker' mystery, Evaluation of local strain evolution from metallic whisker formation (abstract/paywalled). davidwr/(talk)/(contribs)/(e-mail) 04:54, 19 December 2012 (UTC)

Unpaywalled copy of the paper is available here http://sti.srs.gov/fulltext/SRNL-STI-2011-00284.pdf --Nessunome (talk) 00:06, 20 September 2013 (UTC)

Toyota Unintended Acceleration Myth

Please resist contributing to the misinformation surrounding Toyota Camry unintended acceleration recalls. Tin whiskers were *not* responsible for failures despite a few at NASA attempting to find otherwise. NHTSA, NASA, and Toyota all concur on this. Thanks! Prosecreator (talk) 21:51, 11 April 2014 (UTC)

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Alloy whiskers

With the long and relatively trouble-free record of tin-lead alloy solder in the electronics industry, why isn't there any mention of the mitigating effect of a two metal (or more) solid solution versus a polycrystalline single metal? 2600:100B:B13C:9AD7:0:C:51D0:D01 (talk) 22:23, 19 April 2024 (UTC)