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Author: Subject: Making metal powders
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[*] posted on 22-7-2013 at 13:57


well copper is pretty fairly simply as of what i have found it to be..
CuCl2 + HCl + Al
this also produces Cu(I)Cl which can be isolated as a tetraammine where the copper powder will be left as sticky bits in the filter

but for CuZn, the deal is not getting the Cu powder as its mostly not so reactive as the Zn powder
Zn powder can be reacted with S, i have even seen this confined so well that it gave off an actual bang, apart from this it has been used as rocket fuel
it can be used to generate H2S later on (ZnS + HCl)
but if this could be done with other alloys... as in using other metals, even lead, then you could get to very quickly react it to get fx. lead acetate in short time

also recall FeSO4 by CuSO4 + steel wool, in which coated the steelwool with wet copper powder which i got a quite neat amount of




~25 drops = 1mL @dH2O viscocity - STP
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https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 23-7-2013 at 06:22


You can always heat zinc. It will turn brittle above 210 °C and you can smash it with a hammer.



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[*] posted on 23-7-2013 at 19:33


CuZn doesn't really have a weak phase, as far as I know. Beta brass is white, hard, not very ductile, but as far as I know, tends to remain strong.

That said.. the most zinc-rich brass alloy I can find is 40%Zn "architectural bronze", which still has 20% elongation (not as ductile as common 30%Zn "cartridge brass", which is very ductile, up to 50% elongation, maybe even more).

Looking at the phase diagram, I see three intermetallics, corresponding roughly to 47%at, 63%at and 83%at. The latter suggests roughly CuZn5, the others aren't so specific. All of them have a moderate solubility range (even at room temperature), suggesting two things: the electronic bonding and atomic radii are similar (which is true), or the crystal structures are somewhat pliable (which tends to imply a tolerance for slippage and defects, i.e., properties which make metals malleable).

Don't think about Al-Zn: the system is an almost-simple binary eutectic, so all alloys range smoothly from soft zinc, to hard alloy, back to soft aluminum. No help there.

Mg-Zn, however, is useful similar to Mg-Al: there are several intermetallics, all of which have very little (solid state) solubility range. The plot shows Mg12Zn13, Mg2Zn3, a laves phase (MgZn2), and Mg2Zn11. I believe I once made some MgZn2, and it worked very nicely in a pyrotechnic composition: the bright blue-green of zinc, with a bit of extra reactivity thanks to the magnesium. (Any time you see a laves phase on a phase diagram, you can be pretty well assured it's brittle. They aren't necessarily weak -- I'm sure some among the refractory metals are more like cermets in performance -- however, this one you can reasonably guess is weak, given its moderate melting point.)

And, just for completeness, the Al-Mg system shows Al140Mg89, and gamma phase (around 58%at, with some solubility range; in this case, we already know it is a brittle phase, despite it having some range). Both are low melting phases, not much above the lowest eutectic (gamma MP = 736 K).

Al-Cu at 50%wt (i.e., ~Al2Cu) is quite brittle, but with so much (near-inert) copper content, I don't think it's too useful pyrotechnically or chemically. It is useful metallurgically, as it has a low melting point (slightly less than pure aluminum), so is a good way to increase copper content (i.e., a master alloy) in aluminum melts.

Tim




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[*] posted on 24-7-2013 at 05:37


thanks for the inputs
always saw it as being very strange to powder an such hard metal as zinc and sell it in that great quantities, is there any indications of when you have the zinc at 'brittle temperature' so to call it?
i did melt alot of zinc, and i saw it as being very mysterious, because some yellow surface formed on it (C2H2 and O2 was present if that would make a difference) i never found out if it was ZnO or what it was
burned with a blue colour like sulfur, but where would the sulfur come from? the link gave some clearness, got abit lost at it haha

one thing on these metal ratios, are these taken by grammes (Mg Zn2, 100g Mg 200g Zn?) or is it taken as molar ratios?
MgZn sounds like something that could potentially become very very useful, love the sparks and colours zinc gives myself, have dumped many handmade grammes of zinc dust into flames back in time :P

by what i see, magnesium is what holds these brittle intermetallic properties, perhaps it could be run together with something else..? ive seen them write about addind calcium and lithium metal in the range of 10% by weight, calcium seemingly to form a CaO surface that would stop it from burning

who knows, perhaps the zinc could completely take the all toxic barium's place in pyrotechnics if enough people were made aware of this?
i should perhaps tell some persons i know makes magnalium and such stuff at home and sells it in great quantities about this??
i am in fact going somewhere today to get to make some metal bars and such, so i will have a nice amount og zinc from wheel balancing pieces laying around for future testing of this

thanks alot, this is something i need to save (:




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 24-7-2013 at 21:51


Zinc oxide is yellow when hot, white when cool (thermochromic). This can also be seen over molten aluminum alloys rich in zinc, for the same reason (7000 series zinc-bearing alloys are sometimes used in sheet, structural forms and extrusions).

I specified "%wt" when the percentage is by weight, or "%at" when by atomic (molar) ratio. Formulas are explicitly atomic ratio and need not specify. It will be illuminating to study basic chemistry and familiarize yourself with chemical formulas, atomic mass and calculating ratios by atom and by weight.

Magnesium holds no special powers, in and of itself; it is simply the luck of how the atoms fit together. For example, the laves phase requires two slightly different size atoms, and occurs very commonly in all systems with this property, even piles of balls.

I don't know of any Ca and Li bearing magnesium alloys offhand. I've heard of Al-Li alloys before, and Ca is occasionally used, for example to enhance the conductivity of lead, or (along with magnesium, which is more commonly used) to purify and modify iron alloys, mainly to make ductile instead of gray cast iron.

Zinc cannot replace barium because barium has a bright, pure green. Zinc exhibits two primary spectral lines, hence its varying description as some combination of blue and green: neither line is perfectly blue or green, and the ratio of the two varies with conditions, so that some parts of a zinc flame will be bluer or greener than others.

Copper might be a better candidate, having a reasonably green spectral line, but because cooler copper flames tend to be blue, the color would not be very pure, it would tend to be blue around the edges, or turn blue at the end. Blue is also most prominent in the presence of chlorine, a common ingredient in pyrotechnics as perchlorate for example. A green copper composition would have to avoid chlorine.

Tim




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[*] posted on 26-7-2013 at 04:41


infact my whole adventure for so far (but surely continuing later on) went pretty horribly wrong
couldnt get the first bit of aluminium to melt, zinc went fine, nothing yellow seen even
then i put on my much more thick ''steel'' container for getting the al molten
seemingly by the massive fireball that was VERY GREEN at daylight, with the smooth charasteristics of Zn + S somehow, it removed itself in the hot fire
it wasnt steel im pretty sure of
ZnO is yellow when hot, but wouldnt this effect stop when it cools down, because i recovered abit of the can that was somewhat blown apart, and im gonna test for what the hell that thing was, never seen zinc itself go off like that by pure heat, carbon and abit of air..??

the bottom of the beforehand assumed steel also changed colour due to heating, just like iron does, we did melt the zinc and cast it into a bar from that very container, possibly an alloy, even with magnesium in...?
the whole thing started and stopped burning in approx 0.2 seconds

never found anywhere about the atomic ratios, but now that you put it like that it seems too clear, just like you dont write H2O1 but instead H2O

actually one interesting thing about colours is CuCl2
i like CuCl2, so useful for so many things
anyhow about the colours, related to CuCl2, when its put in a fire it gives off both green and bright lightblue flames, i didnt know the temperature had effect on this however, that makes sense why it decides to sometimes give off green instead of lightblue
perhaps the blue is what gives zinc its characteristic green colour, one other thing, there was a sure but very faded smell of sulfur after the metal can went into a mushroom cloud, just further confuses me, could be that they alloyed actual sulfur in metal anyways

i think ill add rough temperature check of flames to my list of what you can use CuCl2 for, as when you have a dispersion of HCl and CuCl2 in a flask with hydrogen and you ignite it, the colour is PURE lightblue, no trace by any means of green, indicating a temperature thats low

another thing, do you know if it by the book (theoretically) would act more blinding if a bright flash was coloured bright green, rather than a less ''bright'' colour spectrum, or less easily detected such as purple or red..?
lately i was blinded by a 1:1:2 KClO4 Ba(NO3)2 MgAl giving a spot lasting for more than 10 minutes, only 5.5 grammes.. and i have had some serious blindings but this was first time i used Ba(NO3)2 in these kinds of things




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 29-7-2013 at 20:00


I've had pretty good experience with iron (II) oxalate. I recommend keeping it under an inert gas atmosphere (I used CO2, but I still need to get a drying tube for it). CO2 is not the best but it's better than air. Upon heating, the iron oxalate decomposes to iron and iron oxide (As mentioned earlier). Would keeping it under a better inert atmosphere keep the oxides from forming?

Iron (II) oxalate is rather easy to synthesize, and it's a good beginning experiment. I've done it several times myself.

http://www.youtube.com/watch?v=_2HHuUMkg58

That's a fantastic video for those who would like to attempt this experiment.




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[*] posted on 30-7-2013 at 12:48


A good milling media is a box of bullets, in the US you can buy all types of stuff for reloading bullets including the slugs. (front bit that shots out), If you buy FMJ's they are lead with a copper coat=no sparks. they come in boxes of 100 for something like 10$



[Edited on 30-7-2013 by Pyro]




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[*] posted on 30-7-2013 at 16:13


On this forum, there has been prior discussion on the use of Ascorbic acid (Vitamin C) on CuSO4 as a path to fine metallic Copper (see for example discussion at http://www.sciencemadness.org/talk/viewthread.php?tid=2654 ).

Here is a reference ( "Preparation of Fine Copper Powder With Chemical Reduction Method and Its Application in MLCC" at http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=42... ) noting not only a path via CuSO4 and Ascorbic acid but also [Cu(NH3)4]++ and Ascorbic acid. To quote:

"In this paper, the preparation of fine copper powder with chemical reduction method was investigated. Polyhedron nonagglomerated monodispersed copper powders by the reaction of CuSO4ldr5H2O and ascorbic acid were synthesized at pH 6~7 and reaction temperature of 60degC~70degC. It was also found by X-ray diffraction (XRD) analysis that a mixture of copper and cuprous oxide could be obtained when [Cu(NH3)4]2+ was reduced by ascorbic acid. Reaction temperature and pH have great effects on efficiency and particle size of copper powders."

Now, this may present a larger number of alternatives to the home chemist as there are many available ways of forming [Cu(NH3)4]++ complex. For example, Cu + aqueous NH3 + H2O2, or Cu + aqueous NH3 + Na2CO3.H2O2, ....One can also prepare a convenient copper salt (like copper acetate from Cu/Acetic acid/H2O2) and add aqueous ammonia to form the royal blue copper ammine complex.


[Edited on 31-7-2013 by AJKOER]
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[*] posted on 30-7-2013 at 16:43


<strong>JKOER</strong>, I linked to that thread on page 2 of this topic (tl;dr? :P). But thanks for finding that reference. I printed it out a few years ago while researching ascorbate redox reactions, but now that I see the title, I might be able to find it. A related paper is available for <a href="viewthread.php?tid=10601&page=28#pid142659">download in <strong>References</strong></a>.

[Edited on 31.7.13 by bfesser]




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[*] posted on 14-12-2013 at 09:42


I just made a ball mill from an electric mixer, but the problem is, it spins way to fast, it turns it into a centrifuge, and does not grind the Al at all.
I can't slow it down any more, but I might be able to add another cylinder to it and that would slow it down, right?
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[*] posted on 14-12-2013 at 11:31


Here is a good video on how to make very fine metal powders.



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[*] posted on 14-12-2013 at 11:42


The video is alright, but the methods employed are labor intensive and far from ideal. For one thing, <em>a file must only be used in one direction</em>! They're only designed to work on a forward stroke of the file (reverse if you're holding the work piece); stroking it back and forth like that causes it to dull, clog, and work very slowly. A file is not a rasp! Second, it's probably easier to improvise a small ball mill&mdash;even hand-cranked&mdash;than to find a suitable steel plate and bar.



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[*] posted on 14-12-2013 at 11:59


that is an unbelievably labour intensive, wasteful and time consuming method.

grinding between those steel plates introduces all kinds of other metal oxides, and it spreads around fine Mg powder.

Just buy powders, If you can't, get someone who can to send some to you. I have more semi fine Mg powder than I will ever need, just U2U me.






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[*] posted on 14-12-2013 at 13:15


As I have said many times in the comments of that video, it is only practical for making very small amounts of fine metal powders. For larger amounts I use, and recommend, a ball mill.
The method remains interesting though, because particle sizes not reached by a week of ball milling is achieved in five minutes. The process is faster and dust and oxidation is prevented by milling under a suitable non-polar solvent. I have for example successfully made nano-thermite with Fe2O3 and magnalium which explodes like the fastest flash powder.
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[*] posted on 14-12-2013 at 18:14


For my copper I make a saturated solution of CuSO4 and drop some iron in there. You can substitute certain metals in this method. The other approach I use is filing metal ingots with a rat tail file.



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[*] posted on 14-12-2013 at 18:34


thebean, try adding salt and aluminum foil (or old drink cans) to your CuSO4. That works a whole lot faster; plus you don't have to scrape copper off the aluminum pieces if they're sufficiently thin.



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[*] posted on 14-12-2013 at 18:58


I think a hand-cranked ball mill would be more labor intensive video's method, but a electric ball mill would be great.;)
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[*] posted on 15-12-2013 at 07:02


Ever heard of gears and pulleys?



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[*] posted on 15-12-2013 at 13:50


Yes, but I think it would time consuming to spin it.
Also, even with gears and pulleys, you cannot spin it too fast or it will no longer work, so you would still have to spin it a long time.
Plus installing a motor would not be that hard.

[Edited on 15-12-2013 by Zyklonb]




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[*] posted on 22-12-2013 at 10:35


I've made a few powders from alkoxides... It's not feasable for those on the higher end of the reactivity series, but for the quality and grain size I've gotten(despite sloppy labwork) it's been worthwhile to learn.
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[*] posted on 12-12-2016 at 11:00


Maybe theres some way it can be made from metal foams
Which maybe brittle because of there structure


http://www.tms.org/pubs/journals/JOM/0012/Banhart-0012.html

https://m.youtube.com/watch?v=8FHTK2LZNTY

[Edited on 13-12-2016 by symboom]
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[*] posted on 21-12-2016 at 09:30


Forming a metal powder increases surface area (and potential reactivity) at the expensive of structural strength. However, I vaguely recall reading about making an alloy and then dissolving the more reactive metal with, say, an acid resulting in the preservation of some structure.

The intended application, per my limited recollection, was electrode construction with the resulting structure providing good surface area.

More general applications are likely possible in other areas where surface area and a larger solid structure are appropriate.

Here is a reference to the apparent method referred to as dealloying, to quote:

"Dealloying or selective leaching refers to the selective removal of one element from an alloy by corrosion processes. A common example is the dezincification of unstabilized brass, whereby a weakened, porous copper structure is produced. The selective removal of zinc can proceed in a uniform manner or on a localized (plug-type) scale. It is difficult to rationalize dezincification in terms of preferential Zn dissolution out of the brass lattice structure. Rather, it is believed that brass dissolves with Zn remaining in solution and Cu replating out of the solution. Graphitic corrosion of gray cast iron, whereby a brittle graphite skeleton remains following preferential iron dissolution is a further example of selective leaching. The term ""graphitization is commonly used to identify this form of corrosion but is not recommended because of its use in metallurgy for the decomposition of carbide to graphite."

Link: https://www.nace.org/Dealloying/

For a recent review of the expanding field of dealloying and dealloying materials, see
http://www.annualreviews.org/doi/abs/10.1146/annurev-matsci-... .

[Edit] In the cited context of fine Zn/S powder, which as mentioned at the top of this page, can be explosive, the employment of a thin Zinc tubes created by dealloying surrounded by sulfur, I would expect a less explosive, slower and possibly more uniform, burn reaction. Related example, a burning Magnesium ribbon in air, except that the structure of the ribbon via dealloying, has been augmented to increase the burn rate.

[Edited on 22-12-2016 by AJKOER]
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[*] posted on 7-1-2017 at 17:25


A Carbide Rotary Burr File on a drill would work but its easier just to buy the powder.

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[*] posted on 19-1-2017 at 01:29


I made a video on zinc powder..

https://www.youtube.com/watch?v=bclTkQzd0Q8




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