"Ignoramus30015"
wrote in
message
...
On 2010-12-23, Phil Kangas
wrote:
Here's the answer I received from a retired
material science guy.
phil k.


Hi Phil,

A few comments to get you started. You probably
have a Chemistry textbook to consult to add
some
details.

Most metals are soluble in mercury and the
alloys
they form are call amalgams. Dentists use
amalgam
filling materials, which are alloys usually
containing silver, tin and copper that have
been
amalgamated with mercury. Aluminum also forms
an
amalgam, that is an alloy formed on contact
which
is aluminum dissolved in mercury.

As you know, aluminum readily forms a thin
oxide
layer at surfaces in air, which is then very
protective against many environments including
air. In this case, there was likely a scratch
or
other defect in the oxide layer that allowed
contact between the mercury and aluminum
leading
to amalgamation. Amalgamation of this type has
often been cited as possible means of aircraft
sabotage during WW II.

Beyond formation of the mercury-aluminum alloy
in
the reaction shown in the video, one could
surmise
that because aluminum is a reactive element,
the
apparent gas evolution could result if there
was
some water present that would permit the
aluminum
in the amalgam to oxidize and hydrogen gas to
form
as part of the reaction to form aluminum
hydroxide
or aluminum oxide.

Hope this helps.

Merry Christmas,
Don




Also check this out :

http://en.wikipedia.org/wiki/Aluminium_amalgam

And to think that there are people out there that
consider metalworking boring...... ! Not around
here though, eih? phil