Wikipedia

Tin pest

Tin pestis anautocatalytic,allotropictransformation of the elementtin,which causes deterioration of tin objects at low temperatures. Tin pest has also been calledtin disease,[1]tin blight,tin plague,[2]ortin leprosy.[3]It is an autocatalytic process, accelerating once it begins. It was first documented in the scientific literature in 1851, having been observed in the pipes ofpipe organsin medieval churches that had experienced cool climates.[4]

Tin medal affected by tin pest

With the adoption of theRestriction of Hazardous Substances Directive(RoHS) regulations in Europe, and similar regulations elsewhere, traditional lead/tinsolderalloysin electronic devices have been replaced by nearly pure tin, introducing tin pest and related problems such astin whiskers.[5][6]

Allotropic transformation

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At 13.2 °C (55.8 °F) and below, pure tin transforms from the silvery, ductile metallicallotropeof β-formwhite tinto the brittle, nonmetallic, α-formgrey tinwith adiamond cubicstructure. The transformation is slow to initiate due to a high activation energy but the presence ofgermanium(or crystal structures of similar form and size) or very low temperatures of roughly −30 °C aids the initiation. There is also a large volume increase of about 27% associated with the phase change to the nonmetallic low temperature allotrope. This frequently makes tin objects (like buttons) decompose into powder during the transformation, hence the nametin pest.[7]The decomposition willcatalyzeitself, which is why the reaction accelerates once it starts. The mere presence of tin pest leads tomoretin pest. Tin objects at low temperatures will simply disintegrate.

Allotropic transformation of tin.
Allotropic forms of tin.

Possible historical examples

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Scott expedition to Antarctica

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In 1910 British polar explorerRobert Scotthoped to be the first to reach theSouth Pole,but was beaten by Norwegian explorerRoald Amundsen.On foot, the expedition trudged through the frozen deserts of theAntarctic,marching for caches of food and kerosene deposited on the way. In early 1912, at the first cache, there was no kerosene; the cans – soldered with tin – were empty. The cause of the empty tins could have been related to tin pest.[8]The tin cans were recovered and no tin pest was found when analyzed by the Tin Research Institute.[9][10]Some observers blame poor quality soldering, as tin cans over 80 years old have been discovered in Antarctic buildings with the soldering in good condition.[citation needed]

Napoleon's buttons

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The story is often told ofNapoleon's men freezing in the bitterRussian Winter,their clothes falling apart as tin pest ate the buttons. This appears to be anurban legend,as there is no evidence of any failing buttons, and thus they cannot have been a contributing factor in the failure ofthe invasion.[11]Uniform buttons of that era were generally bone for enlisted, and brass for officers.[12]Critics of the theory point out that any tin that might have been used would have been quite impure, and thus more tolerant of low temperatures. Laboratory tests of the time required for unalloyed tin to develop significant tin pest damage at lowered temperatures is about 18 months, which is more than twice the length of the invasion.[8]Nevertheless, some of the regiments in the campaign did have tin buttons and the temperature reached sufficiently low values (below −40 °C or °F).[11]In the event, none of the many survivors' tales mention problems with buttons and it has been suggested that the legend is an amalgamation of reports of blocks of Banca tin completely disintegrated in a customs warehouse in St. Petersburg in 1868, and earlier Russian reports that cast-in buttons for military uniforms also disintegrated,[13][10]and the desperate state of Napoleon's army, having turned soldiers into ragged beggars.[11][14]

Modern tin pest since adoption of RoHS

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Re-melted tin affected with tin pest is poured intoingotmolds atRock Island Arsenal Joint Manufacturing and Technology Center,Rock Island, Illinois,in 2017.

With the 2006 adoption of theRestriction of Hazardous Substances Directive(RoHS) regulations in theEuropean Union,California banning most uses oflead,and similar regulations elsewhere, the problem of tin pest has returned,[15]since some manufacturers which previously used tin/lead alloys now use predominantly tin-based alloys. For example, theleadsof some electrical and electronic components are plated with pure tin. In cold environments, this can change to α-modificationgrey tin,which is notelectrically conductive,and falls off the leads. After reheating, it changes back to β-modificationwhite tin,which is electrically conductive. This cycle can cause electricalshort circuitsand failure of equipment. Such problems can be intermittent as the powdered particles of tin move around. Tin pest can be avoided byalloyingwith small amounts ofelectropositivemetals orsemimetalssoluble in tin's solid phase, e.g.antimonyorbismuth,which prevent the phase change.

See also

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  • Bronze disease– destruction of bronze artifacts by corrosion
  • Gold–aluminium intermetallic– giving rise toPurple plagueorWhite plague,another failure mode for electronic components due to the formation of a crystalline substance.
  • Zinc pest– decay of zinc by an unrelated intercrystalline corrosion process.

References

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  1. ^Barthelmy, Michael (1997).Problems With Pure Tin Coatings(PDF)(Report). NASA.
  2. ^Carrlee, Ellen (2003)."Does low-temperature pest management cause damage? Literature review and observational study of ethnographic artifacts".Journal of the American Institute for Conservation.42(2): 141–166.doi:10.1179/019713603806112732.
  3. ^The Organ Yearbook.Vol. 22–23. University of Virginia. 1992. p. 136 – via Google Books.
  4. ^Bucur, Voichita (2019). "Degradation of Organ Pipes and of Brass Instruments".Handbook of Materials for Wind Musical Instruments.Springer. pp. 637–678.doi:10.1007/978-3-030-19175-7_18.ISBN978-3-030-19174-0.
  5. ^Burns, Neil Douglas (Oct 2009), "A Tin Pest Failure",Journal of Failure Analysis and Prevention,9(5): 461–465,doi:10.1007/s11668-009-9280-8,ISSN1864-1245,S2CID136953708,(Print)ISSN1547-7029
  6. ^Tin Pest ControlNational Physical Laboratory,www.npl.co.ukArchived2020-05-05 at theWayback Machine
  7. ^Janey LevyTin,The Rosen Publishing Group, 2009,ISBN1-4358-5073-4,page 20
  8. ^abAdams, Cecil (May 2, 2008)."Did tin disease contribute to Napoleon's defeat in Russia?".The Straight Dope.Retrieved17 August2010.
  9. ^Historic food cans opened.Tin and Its Uses. No. 39, p. 6. 1957
  10. ^abGilberg, Mark (June 1991)."History of Tin Pest:the Museum Disease".AICCM Bulletin.17(1–2): 3–20.doi:10.1179/bac.1991.17.1-2.001.ISSN1034-4233.
  11. ^abcÖhrström, Lars (2013).The Last Alchemist in Paris.Oxford, UK: Oxford University Press.ISBN978-0-19-966109-1.
  12. ^Emsley, John(1 October 2011) [2001].Nature's Building Blocks: an A-Z Guide to the Elements(New ed.). New York, United States:Oxford University Press.p. 552.ISBN978-0-19-960563-7.Only officers had metal buttons, and those were made of brass.
  13. ^Fritsche, Carl (1869)."Ueber eigenthumlich modificirtes Zinn".Berichte der Deutschen Chemischen Gesellschaft.2:112–113.doi:10.1002/cber.18690020156.
  14. ^Zamoyski, Adam (2004).Napoleons Fatal March on Moscow.New York, NY: Harper Perennial.
  15. ^Sampson, Michael J. (2010-06-22).Lead-free Electronics; Impact for Space Electronics(PDF).1st NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop, NASA GSFC, Greenbelt, MD, USA.: NASA.{{cite conference}}:CS1 maint: location (link)
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External videos
tin pest, transformation of beta tin into alpha modification (grey tin)onYouTube
Time lapse video of tin pest on an ingot
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