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Fleaker
International Hazard
Posts: 1252
Registered: 19-6-2005
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Mood: nucleophilic
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Morgan, if you'd like, you can send it to me with return shipping and I can do XRF on it for you. I wouldn't say they have the same properties at
all--each is unique and differs from the other in its own way.
In general, it's virtually impossible to tell by looks Pt vs PtIr without annealing and testing the as annealed hardness--Ir alloy will always be
harder. You might have some luck with the electrical resistivity as well.
If you want to catalytically light stuff on fire for your application, you can get a porous zirconia tube and impregnate it with platinum black.
I also have some spare Pt ink if you want a small bit. It's last application were probably letters on some space shuttle or something 
In other news, those $1000 induction melters on ebay...
like this one in particular,
http://www.ebay.com/itm/15KW-30-80-KHz-High-Frequency-Induct...
they can melt platinum 
Visited a friend and melted ~1000 g chunk.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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Morgan
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Thanks Fleaker, but I don't really need to know what my boats are made of at this time. I came across this tidbit on iridium, which isn't anything
more than what was discussed really.
http://www.technology.matthey.com/resources/view-questions-a...
https://en.wikipedia.org/wiki/Hardnesses_of_the_elements_(data_page)
I am curious how porous zirconia is impregnated with platinum black. I don't have any platinum black but only a gram of Adam's catalyst and
palladium black. I once thought about trying to sinter some platinum powder/dust from my 5% Pt on alumina beads or 1% Pt on alumina powder onto a
piece of platinum wire using electricity if that would retain the surface area? Maybe I could fulgurite my Pt powder somehow with high voltage. I
fiddled with my Pd on alumina pellets drilling a hole in them on my lathe by holding/chucking them inside a tiny piece of plastic tubing and then
drilling with a micro carbide drill bit from my dremel collection and stringing some .002ths Pt wire through the hole but that didn't work. My Pt wire
is at least twice at thick as what the little catalytic lighters use but if you heat it up/get it going, it will light methanol of course. I should
have tried my 5% Pt beads but I never got around to it.
I came across this zirconia potato peeler lamp that I hadn't read about before.
https://www.youtube.com/watch?v=uGxSwumcFtU
https://www.youtube.com/watch?v=1vCQySb6ulA
https://en.wikipedia.org/wiki/Nernst_lamp
That induction heater looks like something nice to have around.
The old days lighter before conventional matches.
http://www.ebay.com/itm/RARE-Mid-19th-c-Dobereiner-PLATINUM-...
[Edited on 19-10-2016 by Morgan]
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Fleaker
International Hazard
Posts: 1252
Registered: 19-6-2005
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Mood: nucleophilic
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I think you'd want some porous zirconia and impregnate with a soluble Pt salt and then give it a once over with an H2 flame would do the trick.
Can kill the flame and see if it lights it again.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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woelen
Super Administrator
Posts: 8014
Registered: 20-8-2005
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Mood: interested
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@Tsjerk: Thanks for the wires. They arrived in good order. I'll try some experiments with them and I'll share the results.
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Morgan
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It seems like if platinized zirconia were enough to light methanol vapor without using a two step method (platinum black or sponge and fragile Pt wire
combination) the people who made the self-starting lighters would have opted for that or a single Pt bead method because the wires are quite easily
damaged. It's just getting around the fragility problem that's troublesome.
I could use a handwarmer platinized wick with Pt wire for starting my jam jars but there's no way that would hold up to the buffeting of combustion
and the fibers would be breaking lose unlike something like a model engine glow plug that is partially sequestered or protected in a cavity of some
sort.
There was a lamp in the 1800's that used a coil of platinum wire about .005ths with a battery to start the heating process and that would ignite the
lamp, say mounted in a hallway. The coil also retracted from above the flame and wick mechanically after ignition. The article stated that the wire
had to be thin enough to light the vapor from the wick yet not too thin as to burn out or have a short life.
In looking at this platinum black bead Ben presents, it almost appears they drilled a hole and put the wire through, as it's an irregular shaped clump
of platinum black and the wire is strung off-centered somewhat. The clumps are quite fragile/friable too. It's curious how they're made, if the
clumps are just pressed into that shape or sintered or the powder maybe hit with a laser for a short bit, perhaps that would be a way of forming them.
Here's a good closeup of the bead. I should say on another lighter I have the "beads" are perfect little cylinder/coin/donut shaped things with a hole
in the middle but still very prone to crumbling if stressed in the least.
https://www.youtube.com/watch?v=8gFqzbnUO-Y#t=29s
https://www.youtube.com/watch?v=UtkEfzpZ4Sg
[Edited on 20-10-2016 by Morgan]
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Morgan
International Hazard
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I wonder through some technology or brass tacks cleverness if you could subdivide the end of a piece of fine platinum wire enough times to reach a
critical surface area enough so that you could light methanol vapor starting from room temperature?
Just some imaginations ...
https://www.mutualart.com/Artwork/Tied-Wire-Branching-Wall-M...
http://bronhebog.blogspot.com/2011/11/branching-out.html
https://sites.google.com/a/aaps.k12.mi.us/kulka/_/rsrc/14727...
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woelen
Super Administrator
Posts: 8014
Registered: 20-8-2005
Location: Netherlands
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Mood: interested
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I did the experiment with tellurite. The result is interesting, but not spectacular to see. I did the following:
- Dissolve some K2TeO3 in water and perform electrolysis on this with platinum anode and platinum cathode.
When this is done, then no gas is produced, not at the anode, nor at the cathode, but a current is flowing. At the cathode, black material settles at
the platinum wire. At the anode, no visible reaction occurs. At the cathode, the tellurium most likely is reduced from its +4 oxidation state to the
elemental state. This leads to formation of black material on the cathode wire. At the anode, the tellurite ion most likely is oxidized to tellurate
ion, which is colorless. This reaction is quite special, because at the cathode, it is an anionic species, which leads to formation of a solid
elemental compound. Normally, such reactions occur with cations, such as metal ions.
The black material could easily be removed from the platinum wire by immersion in 65% HNO3. It quickly dissolves in that.
- Dissolve some TeO2 in conc. HCl. This yields a deep yellow solution, containing the TeCl6(2-) ion. When this is electrolysed with 5.5 volts, then
quite a large current flows through the thin wires and there is fast bubbling at both wires. At the anode, chlorine is formed (smell), at the cathode,
hydrogen is formed. No elemental tellurium is formed. However, after half a minute or so, there was a very peculiar smell, which was clearly
noticeable besides the smell of the chlorine. It is a very familiar smell, but I do not remember from which plant or food it is coming. It is,
however, something which I know from food or plants. The smell is quite strong and quite unpleasant. I immediately stopped the experiment and opened
the window and left the room for a while. This smell most likely is due to some volatile tellurium compound, maybe H2Te. Tellurium is not exceedingly
toxic, but it can make you very smelly for quite a long time, so I did not take the risk of that and quit the experiment.
I also tried experiments with vanadate(V) ion in an excess of a solution of NaOH. This solution is colorless. Vanadate ion can be reduced to
hypovanadate ion (V4O9(2-)) in alkaline solution. This ion has a deep brown/red color. With the platinum cathode, however, no visible formation of
hypovanadate occurs, nor any metal is formed. Hydrogen gas escapes at the cathode.
Next, I stronly acidified the solution, so that it becomes acidic. This leads to formation of "pervanadyl" ion, VO2(+), which is yellow. This is no
real peroxo species, it has the prefix "per", because there also is a vanadyl ion VO(2+), which is blue. I tried to make VO(2+) from the VO2(+) in
acidic solution, but this also does not work. You simply get H2 at the cathode.
More experiments will follow . . .
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Tsjerk
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Good to hear they arrived.
Maybe the plant smell you are looking for is garlic? I have heard of comparisons with garlic.
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