Learn something new every day - Tin Pest

[TerraHertz]

'Tin Pest' - the transformation of beta tin into alpha modification (grey tin).


http://www.periodictable.ru/050Sn/Sn_en.html

This what happens to white tin under 13.2°C. The ductile white tin transforms into another allotrope, the brittle and bulkier gray tin.

How did I get to be 58 years old and never heard of this before?
How many others hadn't heard of it?

Apparently all the people responsible for the ROHS legislation that resulted in pure Tin being used in electronics.
I knew about Tin Whiskers growth, but not this. So, any components containing pure Tin are pretty much junk below 13.2°C, is that right? As well as highly unreliable after some number of years due to conductive whisker growth.

Also google: Robert Scott's Antarctic expedition tin pest

[sleemanj]

This what happens to white tin under 13.2°C.

Where do you get that?  The video is at -40°C

    "Machined piece at -40°C. 1 second of video correspond 1 hour of real time, 20 frames per hour. Grid size - 1 cm."

[BravoV]

How did I get to be 58 years old and never heard of this before?
How many others hadn't heard of it?

Not many I believe, but I did, remembered I was amazed by the story when I was a kid reading a science facts book about the tin buttons that were used at clothing that disintegrated into dust in freezing cold. 

Source -> http://en.wikipedia.org/wiki/Tin_pest

[JoeO]

This what happens to white tin under 13.2°C.

Where do you get that?  The video is at -40°C

    "Machined piece at -40°C. 1 second of video correspond 1 hour of real time, 20 frames per hour. Grid size - 1 cm."

-40C is -40F

[mariush]

I knew about it.  It was in a QI episode some time ago and they were saying something about wagons with aluminum going through cold Russia (or another European country, maybe Germany) and arriving at destination with the wagons/cargo destroyed.

[TerraHertz]

This what happens to white tin under 13.2°C.

Where do you get that?  The video is at -40°C

    "Machined piece at -40°C. 1 second of video correspond 1 hour of real time, 20 frames per hour. Grid size - 1 cm."

The 13.2 deg C came from some site I was reading. Didn't check it then, but now I did:
  http://en.wikipedia.org/wiki/Tin

?-tin (the metallic form, or white tin), which is stable at and above room temperature, is malleable. In contrast, ?-tin (nonmetallic form, or gray tin), which is stable below 13.2 °C (55.8 °F), is brittle. ?-tin has a diamond cubic crystal structure, similar to diamond, silicon or germanium. ?-tin has no metallic properties at all because its atoms form a covalent structure where electrons cannot move freely. It is a dull-gray powdery material with no common uses, other than a few specialized semiconductor applications.[4] These two allotropes, ?-tin and ?-tin, are more commonly known as gray tin and white tin, respectively. Two more allotropes, ? and ?, exist at temperatures above 161 °C (322 °F) °C and pressures above several GPa.[6] In cold conditions, ?-tin tends to transform spontaneously into ?-tin, a phenomenon known as "tin pest".

I guess the very low temp for the video was to make the process go faster. Counter-intuitive as that may seem.

Edit. Huh. The Greek letters in the quote died. Oh well, see the source.

[PedroDaGr8]

As a chemist I thoroughly enjoyed this. It seems as if tin is a proto-metalloid (my own term) in that it's metallic in one allotrope and non-metalic in the other. This region of the periodic table is where all the word fun stuff happens. Much of it due to the weird orbital transitions that arise (gold is yellow, mercury is a liquid are two prime examples).

[T3sl4co1l]

Now now, let's not forget plutonium, the metallurgist's dream.  Pure, it goes through five phase transitions before melting!

Tim

[daqq]

I knew about this, but I haven't seen a video! Thanks!

Another fun thing to watch is how mercury likes alluminum: