Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: katieHaylor on 03/10/2017 09:34:22

Title: What is in aluminium?
Post by: katieHaylor on 03/10/2017 09:34:22: Karen wants to know:

Is there palladium in aluminium?

Can you help?
Title: Re: What is in aluminium?
Post by: Kryptid on 03/10/2017 14:47:07: No, aluminum is its own chemical element. It has an atomic number of 13 on the periodic table.
Title: Re: What is in aluminium?
Post by: syhprum on 03/10/2017 17:12:49: I think Karen may be thinking of Duralumin an alloy used in the construction of WWII aircraft
Title: Re: What is in aluminium?
Post by: Colin2B on 03/10/2017 17:35:58: It is possible to alloy palladium and aluminium and I have seen this proposed for use in jewellery.
Not aware that it is a naturally occurring impurity in the processing of aluminium.
Title: Re: What is in aluminium?
Post by: chiralSPO on 03/10/2017 17:50:41: There are intermetallic compounds of aluminum and palladium, but I don't think any can really be thought of as alloys. I would have to look at a phase diagram to say for sure, but there may be true alloys that are mostly one with a tiny impurity of the other dissolved in it... or they might even be immiscible! (for instance iron and bismuth are immiscible)

Palladium is much more electronegative than aluminum, so the two elements will not share electrons very evenly (Pd atoms will have excess electron density, and Al atoms will be electron deficient).

A mixture of aluminum and palladium powders will react with each other quite exothermically (this was discussed previously on the forum here: https://www.thenakedscientists.com/forum/index.php?topic=20765.0 )
Title: Re: What is in aluminium?
Post by: chiralSPO on 03/10/2017 18:02:38: Since the video referenced in the link I included in my previous post is no longer active I have included this one:

and here is the phase diagram for Pd and Al:

1-s2.0-S0925838812023894-gr11.jpg (22.73 kB . 374x266 - viewed 4151 times)
L = liquid
other phases described here:

Screen Shot 2017-10-03 at 1.01.51 PM.png (149.71 kB . 1448x650 - viewed 4314 times)
both from this paper: http://www.sciencedirect.com/science/article/pii/S0925838812023894#t0005
Title: Re: What is in aluminium?
Post by: jeffreyH on 03/10/2017 18:13:10: Is there any aluminium in the London Palladium or is it just reserved for Turkey?
Title: Re: What is in aluminium?
Post by: vent on 16/10/2017 09:54:45: Why are these two elements alloyed though? Are there any advantages?
Title: Re: What is in aluminium?
Post by: evan_au on 16/10/2017 10:53:28: Quote from: vent
Why are these two elements alloyed though? Are there any advantages?
Most pure metals are fairly soft - their uniform-sized atoms can slide past each other when the metal is bent.

However, if you put in a few percent of a different atom (with a different size or electron structure), the atoms don't slide past each other as easily, and the alloy becomes much harder than the original metal.

Other advantages for some alloys could include a lower melting point (so it is easier to manufacture), or corrosion resistance.

There are many different metals that could appear in an alloy, either due to natural impurities in the ore, or due to intentional addition of other metals during refining. Designing new alloys is a specialist skill.

See: https://en.wikipedia.org/wiki/Alloy
Title: Re: What is in aluminium?
Post by: Bored chemist on 16/10/2017 17:48:29: Interestingly, and somewhat unusually, the equimolar PdAl alloy has a slightly higher melting point than the constituents.

http://www.himikatus.ru/art/phase-diagr1/Al-Pd.php
Title: Re: What is in aluminium?
Post by: vent on 20/10/2017 12:07:15: Ah thanks for the answers!! I just assumed there must be some special advantages...
Title: Re: What is in aluminium?
Post by: adianadiadi on 08/01/2018 18:33:29: Palladium may be present as impurity in commercially available aluminium.
Title: Re: What is in aluminium?
Post by: Bored chemist on 08/01/2018 19:15:36: Quote from: adianadiadi on 08/01/2018 18:33:29
Palladium may be present as impurity in commercially available aluminium.
Are you planning a series of about a hundred posts making that assertion about every element in the periodic table, or is there something special about palladium?