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I used to work with tungsten carbide cubes during my PhD thesis. They're used in multianvil high-pressure synthesis. With the right setup you can reach almost 2
by MgB2 5y ago
I used to work with tungsten carbide cubes during my PhD thesis. They're used in multianvil high-pressure synthesis. With the right setup you can reach almost 20 GPa of pressure. Not as much as with diamond anvil cells, but you have more reasonable sample sizes (a few milligrams). And thats still like the pressure pretty deep into Earth's mantle.
I also used the opportunity to snap a neat picture of a polished WC cube: https://imgur.com/C2YiMqb.jpg https://imgur.com/C2YiMqb.jpg
I always had fun handing them over to students because everyone is surprised by the sheer weight of these things.
Tungsten carbide is actually quite dangerous after it has been subjected to a lot of stress (Such as being stuck into a 1000 t press for a high-pressure synthesis). They have the mean tendecy to explode into super sharp pieces when you're not expecting it, so wear goggles.
- kragen 5y agoOh, that's really interesting! I guess the energy is storred in them because they underwent some plastic deformation in the press? Is that from plasticity of the WC itself or from a sintering aid such as cobalt? I would have thought pure WC would have no plasticity at all at room temperature or anything nearby.
- fywacro 5y agoFYI, tungsten carbide (tungsten + carbon) is a different substance from the pure metal tungsten... They have very different physical properties. But I do appreciate your story about tungsten carbide, too :-)
- paulgerhardt 5y agoIf anyone knows where to get a tungsten cube I would be interested. I’ve wanted one since reading this post a few years ago but every vendor usually sells alloys.
- falcrist 5y agoI honestly wouldn't have noticed that the Midwest Tungsten Service products weren't pure tungsten, but when I went back to the amazon page, I found a note from the seller: >The tungsten sphere is 90% tungsten with nickel/iron for the remainder, the aluminum sphere is 6061 alloy. This actually seems to apply to most of their products. Not just the spheres. If you search Amazon for "pure tungsten", you'll find vendors selling cubes that are at least more pure than this vendor's stuff. There are also other items that claim to be high purity tungsten.
- daerhan 5y agoThis vendor sells cubes of various sizes that they claim to be 99.95% tungsten - https://luciteria.com/metal-cubes/tungsten-cube https://luciteria.com/metal-cubes/tungsten-cube. I have one of the 1cc cubes and it seems to be of good quality. They also sell a lot of other exotic elements.
- paulgerhardt 5y agoPerfect, thank you! Looking it seems they both have a kilo of pure tungsten in cube form measuring 38.1mm^3 or a kilo of tungsten carbide measuring 40mm^3.
- HarryHirsch 5y agoCan't blame them for selling alloy. Pure tungsten is extremely brittle and virtually unmachineable. So they'll sell you nickel alloy, because you can work that to tolerance. No powder metallurgy required.
- tyingq 5y agoAliexpress, with the usual gamble as to what you actually receive :) https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20210826190415&origin=y&SearchText=tungsten+cube https://www.aliexpress.com/wholesale?catId=0&initiative_id=S...
- fraa-orolo 5y ago> FYI I'd wager they're fully aware of the differences between tungsten carbide and pure tungsten, having done a doctorate about it.
- User23 5y agoThe FYI might be poor phrasing, but GP is right that many people confuse the two. This isn't helped by many sellers of novelty "tungsten" online selling tungsten carbide and mentioning it in the fine print, if at all.
- dvaun 5y ago> They have the mean tendecy to explode into super sharp pieces when you're not expecting it, so wear goggles. Well, I guess I need to buy a new wedding ring at some point.
- hutzlibu 5y agoYour marriage yields the equivalent of 1000t pressure stress on your wedding ring?
- toiletaccount 5y agoi read something about a guy shattering his tungsten wedding band on his wedding night, after deciding that slapping his hands on concrete was how you're supposed to dance. professional advice: don't use an exotic metal for your wedding band. some fire departments can't cut it if your ring finger swells up.
- downrightmike 5y agoEasy enough to cut the finger off and reattach later. Seriously that's what they do.
- Brendinooo 5y agoTungsten (carbide) ring wearer here: I've looked into this and supposedly they're easy enough to crack. Lucky for me, I bought mine for ~$30 on eBay and it's always been a bit too big for me. If my finger only swells a bit, it could probably still come off.
- dreamcompiler 5y agoOr you could just not wear rings at all. I'm an EMT and the only trauma injury that gives me the creeps is degloving. Happens e.g. when somebody falls off a ladder and their ring gets caught on a nail on the way down. Don't google it.
- thaumasiotes 5y ago> They have the mean tendecy to explode into super sharp pieces when you're not expecting it, so wear goggles. This seems understated. Shouldn't you also wear armor?
- danielheath 5y agoA 3mm deep cut 2cm long will heal just fine on your arm with minimal first aid. You’ll be lucky to keep an eye with the same injury even with an excellent surgeon.
- NL807 5y agoThose things look awesome. What's cost of getting one of these?
- ncmncm 5y agoIt is, for all practical purposes, impossible to buy an actual tungsten ring; all sold as "tungsten" are really just tungsten carbide ceramic. Really-pure elemental tungsten is not difficult to machine, unlike common tungsten alloys. A company near Los Angeles, American Metals, will sell you a 0.99999 pure tungsten boule for a few $thousand. You can ask for it to have a nominal (e.g.) 22 mm outer diameter, and slice it up and core out a collection of rings. The boule melt pattern on the outside is really appealing. You can sell the rest of the rings, then, provided you can find a way to cut through the noise of the $2 tungsten-carbide hawkers. You might be tempted to paint on a design with resist and electro-plate gold where it isn't. The scrap you cored out is pretty valuable. Maybe have the cores cut out as discs, instead of just drilling, because the "swarf" would be really hard to melt! They would resemble very heavy, thick coins; you can use a CNC machine to mill designs onto them, if you like.
- nextaccountic 5y ago> They have the mean tendency to explode into super sharp pieces when you're not expecting it, so wear goggles. Will goggles really help? This sounds like it would rip your whole face..