Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Mercury and Aluminium
Craig
Harmless
*




Posts: 8
Registered: 4-5-2005
Member Is Offline

Mood: No Mood

[*] posted on 10-5-2005 at 16:32
Mercury and Aluminium


Hi,

I've been experimenting with mercury and aluminium. Some websites say that a violent reaction will take place when mercury comes into contact with aluminium, but sadly this isn't the case :(.

Here's some photo's of the results:








To get the process started I need to use gallium. I always end the process by applying water. I think the gallium only helps the mercury when it is in a liquid state. In the above images the gallium was only a liquid for a short period of time. Sometime soon I plan to do more experiments while keeping the gallium in a liquid state. I also plan to use alternatives to gallium.

You can see the fullsize images, as well as others, on my website:

http://www.craigsarea.com/hg_al.html

The page is still under construction, so some of it is missing.

Hope you find it interesting :).
View user's profile Visit user's homepage View All Posts By User
neutrino
International Hazard
*****




Posts: 1583
Registered: 20-8-2004
Location: USA
Member Is Offline

Mood: oscillating

[*] posted on 10-5-2005 at 17:13


Very interesting. I would have thought that more damage would have been done to the aluminum, as Theodore Grey preformed about the same thing with a larger block and had very fast and complete results. Different aluminum, maybe?
View user's profile View All Posts By User
runlabrun
Hazard to Others
***




Posts: 172
Registered: 4-12-2004
Member Is Offline

Mood: No Mood

[*] posted on 10-5-2005 at 17:14


What is it supposed to do?

-rlr

[Edited on 11-5-2005 by runlabrun]
View user's profile View All Posts By User
neutrino
International Hazard
*****




Posts: 1583
Registered: 20-8-2004
Location: USA
Member Is Offline

Mood: oscillating

[*] posted on 10-5-2005 at 17:29


Something like this. IIRC, the beam 'rusted' half away in 1.5 hours.
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 10-5-2005 at 17:48


His beam also ended up brown, too... I don't see how that happened.

Must be alloy has something to do with it - numbers 1199 (4n pure), 2024 (alloyed with copper), 7075 (zinc) and 320 and 390 (silicon) might be worth a shot.

I bet you high silicon (390 is 20%) leaves a grainy fluff behind. ;)

Tim
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
BromicAcid
International Hazard
*****




Posts: 3147
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline

Mood: Rock n' Roll

[*] posted on 10-5-2005 at 18:59


As has been mentioned elsewhere on this forum and in other places with straight mercury the reaction is fairly slow, but the addition of a small amount of 'corrosive sublimate' speeds it up greatly. I believe John WW mentioned it.



Shamelessly plugging my attempts at writing fiction: http://www.robvincent.org
View user's profile Visit user's homepage View All Posts By User
Craig
Harmless
*




Posts: 8
Registered: 4-5-2005
Member Is Offline

Mood: No Mood

[*] posted on 11-5-2005 at 04:13


Quote:
What is it supposed to do?


If you do a google for mercury and aluminium you'll find loads of websites that talk about the mercury attacking the aluminium. Some even say a violent reaction will take place. You will also find a lot of contradictory results. But I noticed there are very few photos of the process. I just wanted to see what happened for myself.

Quote:
Very interesting. I would have thought that more damage would have been done to the aluminum, as Theodore Grey preformed about the same thing with a larger block and had very fast and complete results. Different aluminum, maybe?


Theodore Grey was the one who recommended using the gallium. In his video you can actually see the gallium at the start.

From what I've seen, it seems that the gallium only helps when it is in a liquid state. While the gallium is a liquid it mixes with the mercury, but when it turns solid it seperates from the mercury. Maybe in Theodores video he kept the temperature high enough to keep the gallium in a liquid state throughout the whole of the process. In my experiments the gallium was turned to liquid by heating it, but the heat wasn't continually applied, so it quickly turns back to a solid a few minutes into the experiment.

My experiment starts off like Theodore's, but doesn't go for as long. It effectively stops or slows right down. And I think this is because of the gallium, but I haven't yet double checked.

Quote:
His beam also ended up brown, too... I don't see how that happened.


I'm wandering if that's due to the gallium. If you pour liquid mercury onto liquid gallium you get a dirty greyish colour. Maybe the dark colour, or the brown, is actually from the gallium. But that's only a guess, so I might be totally wrong :). Certainly if you handle gallium you get dirty hands :).

I've got some alternatives to gallium, which I'll try soon. It'll be interesting to see if the brown still appears when the gallium isn't used.

Quote:
I bet you high silicon (390 is 20%) leaves a grainy fluff behind.


The heat sink left a grainy light fluff behind whereas the bars left more of a powder. Could heat sinks have silicon in them?

I've asked a few aluminium companies if you would like to donate some aluminium samples, but none have replied yet :(. The trouble is I don't know the precise properties of the aluminium I'm using. If I had all the different types, along with their properties, I could do more acurate experiments.

[Edited on 11-5-2005 by Craig]
View user's profile Visit user's homepage View All Posts By User
garage chemist
chemical wizard
*****




Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline

Mood: No Mood

[*] posted on 11-5-2005 at 05:11


As BromicAcid said, I'd suggest you make some HgCl2, this is much more effective in attacking aluminium because the Hg is generated in intimate contact with the aluminium (be careful though, wear gloves!).
Metallic mercury has great trouble to amalgamate with aluminium, because of the oxide layer. Some HCl might help to remove it (but it forms again in a split second, so first drip some HCl on the aluminium and then apply a drop of mercury while the HCl is still fizzing).

You should be able to get it to work without gallium!

[Edited on 11-5-2005 by garage chemist]
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 11-5-2005 at 09:41


If worse comes to worse I could send you some samples from my aluminum pile. Or vice-versa, someone could send me mercury (which I wouldn't mind ;) ).

Heatsinks may or may not have silicon in them - depends if it was extruded or cast. If it's mostly fins arranged in one direction, especially with serrated surfaces, it's probably extruded. Let me put it this way - can the item be cast between two or more mold halves, or would its shape make more sense for it to be extruded then machined?

Tim
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
uber luminal
Hazard to Others
***




Posts: 124
Registered: 25-8-2004
Member Is Offline

Mood: No Mood

[*] posted on 11-5-2005 at 22:28


Its not really the need for Ga or Hg on Al.

Its the need for a liquid metal who's phase diagram shows intermetallic phases with the metal to be "attacked", which has a lower MP than the base metal, and there is heat or mechanical stress applied.

With the application of stress to the base material, the liquid metal can run through the boundaries and simply seperate the crystals. Thats all it does. It causes the crystals to come apart and sometimes be attacked by air. While Al has its awesome Al2O3 barriar, the liquid doesnt care once its through (since air is still not able to penetrate to create the new Al2O3). Once in the metal it can break apart the crystals such that air can penetrate the pours after the liquid has left the area. The grey junk you see is the Al2O3 coating the little crystals.

I have several samples on my desk showing LME in Cu/Fe, Ga/Al and Ga/Cu. you can spread the LME directionaly by application of stress in the right places. try getting the Ga (I would never use Hg...) on a warm piece of Al following the steps below, and stress the Al by slightly bending it. If you use Hg, wear gloves... at the very least)

for the low MP metals to be used for LME, you dont need to mix the Ga and the Hg... or have the Hg as HgCl. All you need to do is place the molten meltal on the surface of the metal, and use a paper clip or knife to cut the surface of the metal to be 'attacked' from inside of the molten metal. For example... Ga on Al. Warm the Al piece such that the Ga stays molten(rather than Al getting rid of the heat needed to keep the Ga liquid) Place a SMALL blob/dab on the surface of the Al. Insert a sharp metal object (that has a hardness greater than Al) into the Ga blob. Scratch the Al surface, to penetrate the Al2O3 layer. Air will not be able to get to the Al since the Ga is ontop of it (haha!) apply some stress. have fun. Just don't do anything news worthy... and ruin this for the rest of us.
View user's profile View All Posts By User
Craig
Harmless
*




Posts: 8
Registered: 4-5-2005
Member Is Offline

Mood: No Mood

[*] posted on 12-5-2005 at 13:35


Quote:
As BromicAcid said, I'd suggest you make some HgCl2


This is something I plan to do in the future.

Quote:
Some HCl might help to remove it


I ordered some replacement HCl almost 2 weeks ago and I'm still waiting for it to arrive :mad:.

Quote:
If worse comes to worse I could send you some samples from my aluminum pile.


Thanks for the offer :), but it's probably more trouble than it's worth. If I harass enough aluminium companies I'm sure I'll get some samples in the end.


To be honest, there were some parts of the process that didn't really make sense, but Uber Luminal's answer has made things clearer. I'll probably use some of what you've said on my webpage :).
View user's profile Visit user's homepage View All Posts By User

  Go To Top