Realities of diamond armor

[janusmaxwell]

A general question for any system or setting. Diamonds are the hardest substance known to man and the only way to process diamonds is by using diamonds, but does this mean in a non-magical setting that using diamonds for armor and weapons would actually work?

I ask because it seems to crop up in many many scifi or fantasy settings and I had the thought that in a more realistic setting diamond armor or weapons wouldn't be as effective. The idea that keeps jumping at me is that harder objects can't absorb impacts the way softer materials can and a diamond weapon would snap in half too easily and Diamond armor wouldn't absorb the kinetic energy from a blow well enough to protect as well as steel or some other derivative.

Am I on the right path? Or would diamond armor and weapon in a semi-real setting be just as "Super Effective!" As could be assumed?

[JusticeZero]

Glass is also extremely hard, much harder than wood. Introduce a baseball bat to a window and see which one wins.
A major reason why they use steel for swords and armor is because steel is bendy without snapping. Bronze can be very hard, but when it bends, it stays bent. A material which shatters the moment it has to deal with too much force isn't going to be very useful.

[Glimbur]

So, there's a couple things to consider for armor. Hardness is nice, because it means your armor resists scratching/deformation (depending on your definition of hardness). Armor made of cheese would be scratched by a sword so much that it would not help much. But there is also toughness, which is a measure of how much work it takes to break something. Diamonds have bad toughness (or they are brittle), so they can be broken by force like, say, a war hammer to the chest. So, if your enemy will attack you with abrasion (blasts of sand, for example) where hardness is the main requirement then diamond would be fine. But if your enemy is going to use conventional weapons, your diamond armor will break. Rapidly.

Incidentally, there are lots of ways to process diamonds. Jewelers typically break them by hand with non-diamond tools. Just another consequence of the difference between hardness and toughness.

[Spiryt]

In the first place, forming anything resembling wearable armor from diamond is a major achievement.


What are the biggest pieces of diamond people can synthesize, and how any thousands of $$$ does it cost?


And if some super-technology can do it reliably and afford-ably, then, like you've mentioned, it's also way beyond point where it can also simply shatter pieces of diamonds with good ol' high KE bullets.

[Studoku]

Google "Carbon Nanotube Armor". It's like diamond armor, right?

[Kazyan]

The larger an object gets, the easier it is to fracture it if the force is on the same relative scale. You can drop a glass marble from a few feet and it will probably survive, but the optical glass in Hubble-size telescopes needs to be cooled down to operating temperature over a period of, like, a year to avoid the thermal expansion differential fracturing it. The same applies to diamond. If you make a breastplate out of solid diamond somehow, you could probably break it with a fist-sized rock. It would not be very effective.

[janusmaxwell]

Google "Carbon Nanotube Armor". It's like diamond armor, right?

That was actually the way my brain was heading on the matter. Some type of super armor, except my visualization was the Diamond armor would be superior...until I got my question answered here and realized diamond armor is wildly impractical.

[sktarq]

Google "Carbon Nanotube Armor". It's like diamond armor, right?

Far closer to graphite armour.

also. People forget that steel is made up of a bunch of steel (carbon strengthened iron crystals) suspended in basically iron glass. Diamonds fused like that (a massively gletzed crystal) wouldn't absorb energy the same way and just shatter like a just like a solid crystal. I suppose diamond coatings could be useful for increased hardness.
The whole concept of "diamond" armor is almost always a good sign of fantasy/sci-fi gamers/authors who don't know enough about basic science to be able to be taken very seriously.

[Ravens_cry]

It's not really either, as graphite is thin (atom thick I believe) horizontal latices of carbon atoms held together by relatively weak vertical bonds, while carbon nanotubes are lattices of carbon atoms rolled into, well, a tube.
Diamond's structure is different again.

[veti]

Making anything useful-sized out of diamond has never been a practical possibility. If you could devise some magic that could create diamond, as a single flawless crystal, in any arbitrary shape you wanted - then you could make armour out of it, and it'd be very, very good armour. However, if you took a strong enough blow to the armoured region, you'd still suffer severe trauma because the whole force would immediately be transferred to whichever parts of your body the armour was fitted to - there's no elasticity to absorb the impact.

What you can do (and I think this has been done, historically, though I'm not sure) is to encrust a regular metal piece of armour with small diamonds. How much this improves your defence is debatable, but it would have some effect: light blows (i.e. most of them, in practice), if they happened to hit a diamond stud, would not scratch or dent, and they would tend to blunt the attacker's weapon.

As with any crystal, there are two aspects to a diamond's strength. There's the raw hardness (which is unbeatable) - and then there's the flaws. The flaws are what makes the diamond brittle, and make it possible to cut and shape it. The bigger the diamond, the more flaws it's likely to have. So the "perfect unbeatable hardness" thing only applies to a flawless diamond, and the largest one of those in existence (as far as I know) is the De Beers Centenary Diamond, which weighs in at a massive 55g (about 2 oz). So it's hard to imagine using it for armour, for anything larger than a very small baby pixie.

Using diamond for weapons is - only marginally more feasible. There are such things as diamond saws and knives - the saws are hard-wearing, but not particularly sharp, and the knives are extremely sharp, but very brittle. Neither one would be particularly useful as a sword. If you want to know how that might work in practice, take a look at the Aztecs - the obsidian they used for weaponry was not unlike diamond, in that it was very hard and formed a very sharp edge. It worked extremely well for their purposes, but proved completely useless against European metal armour. (And, significantly I think, even the Aztecs never tried to make armour out of obsidian.)

[warty goblin]

Diamond saws for cutting rock etc are a hard steel disk with very small diamonds embedded in the edge. They aren't even sharp in a conventional sense; since it doesn't have macroscopic teeth like a regular saw. It would be an effective weapon in the sense that it would cut flesh apart effectively, but so would just about any other big coarse steel disk spinning at a couple thousand RPM. It would also be a terrible weapon because they're monstrous heavy, and extremely difficult to maneuver thanks to the gyroscopic effects of that big spinning steel disk.

[janusmaxwell]

Picturing something now...regarding the diamond weapon...What if you had a sword that was made of some durable metal to absorb impacts, but the cutting edge was an almost micro thin line of diamond, shaped into a razors edge so the blade could still absorb impact but could cut through freaking anything?

[veti]

Picturing something now...regarding the diamond weapon...What if you had a sword that was made of some durable metal to absorb impacts, but the cutting edge was an almost micro thin line of diamond, shaped into a razors edge so the blade could still absorb impact but could cut through freaking anything?

That's theoretically possible. It would be phenomenally expensive to make, even with modern technology, never mind pseudo-medieval smithing techniques. My gut instinct is that it would still chip with wear (because of the flaws in the crystal), and having chipped, it would be impossible to sharpen it by any normal means - you'd basically have to go through the whole making process all over again.

It would be very, very sharp, and it would be a thing of intimidating beauty to look at.

[Glimbur]

Far closer to graphite armour.

also. People forget that steel is made up of a bunch of steel (carbon strengthened iron crystals) suspended in basically iron glass. Diamonds fused like that (a massively gletzed crystal) wouldn't absorb energy the same way and just shatter like a just like a solid crystal. I suppose diamond coatings could be useful for increased hardness.
The whole concept of "diamond" armor is almost always a good sign of fantasy/sci-fi gamers/authors who don't know enough about basic science to be able to be taken very seriously.

How pedantic do we want to get here? A 'glass' is an amorphous solid; but steel is made up of many tiny crystals. A crystal is a particular arrangement of atoms which repeats; the iron atoms make the crystal lattice and the carbon atoms hang out in it and distort things. Or they form carbides, depending. The advantage to steel is that it can deform, which takes up a bunch of energy. Unless it's too hard, of course, but there's a lot of 'unless' in materials.

Picturing something now...regarding the diamond weapon...What if you had a sword that was made of some durable metal to absorb impacts, but the cutting edge was an almost micro thin line of diamond, shaped into a razors edge so the blade could still absorb impact but could cut through freaking anything?

Historical people in the New World did this, sort of, with obsidian shards stuck into a wood club. It works alright, the problem is that your shards can chip and break. Now that I read more of the thread, I see that these were already mentioned. So it goes.

[LibraryOgre]

Picturing something now...regarding the diamond weapon...What if you had a sword that was made of some durable metal to absorb impacts, but the cutting edge was an almost micro thin line of diamond, shaped into a razors edge so the blade could still absorb impact but could cut through freaking anything?

More or less the idea behind Shadowrun's monofilament swords.

Shadowrun also had Dikote, which put a thin layer of diamond over conventional melee weapons, letting the weapon cut through harder substances.

[warty goblin]

Picturing something now...regarding the diamond weapon...What if you had a sword that was made of some durable metal to absorb impacts, but the cutting edge was an almost micro thin line of diamond, shaped into a razors edge so the blade could still absorb impact but could cut through freaking anything?

Somebody whacks the flat of your expensive sword with a couple bucks of rebar. The resultant vibrations and flexing in your blade cause your edge to shatter. Now you have the world's most expensive butterknife.

You could mitigate this problem to some extent by using a microlith sort of construction, where instead of a single continuous edge, you used shorter blades socketed into the blade one after the other. So long as the individual blades were short enough to survive routine blade flexing without breaking, your weapon won't completely disintegrate the first time some uncooperative person whacks it with a baseball bat.Then your weapon survives until you hit something a couple times with it, after which you're still stuck holding a high-tech butterknife.

And you still won't be able to cut through freaking anything. You'll be able to cut the materials you could already cut, marginally better. For cutting freaking anything you just plain need more power on the edge than a human arm can deliver. To deliver this sort of force in a combat setting, you really need power armor or something similar. In which case you basically want a bigass grinding blade of some sort. Diamond carbide or diamond impregnated steel are popular choices here. You may also have luck with hydraulic sheers, but in that case you're limited to severing things you can get the sheers around.

[Gildedragon]

Yeah as people have pointed out:

Hardness != Durability/Sturdyness != Sharpness

Take obsidian: sharpest thing before industrial materials, a freshly knapped flake is atoms thick at the edge. Thing cuts like nobody's business (better than surgical steel to the point obsidian knives are used for eye surgery)
but you only get a handful of cuts from how quick it loses its edge.

Diamond would be something mixed into the steel to have it keep its edge, but you want something sturdier to be doing the cutting, otherwise it will break.

[Broken Crown]

The idea that keeps jumping at me is that harder objects can't absorb impacts the way softer materials can

This is essentially correct. Hardness and brittleness tend to go hand in hand. In materials engineering, there's normally a trade-off between strength (how much force it takes to break something) and toughness (how much energy it takes to break something); different materials are suitable for different tasks. Diamond (high strength and hardness, but low toughness) is most definitely not suitable for armour.

Diamond would probably work nicely as the outermost layer of a composite armour, presuming you could make diamond plates of a suitable size and shape (which is getting within the reach of current technology; synthetic diamonds have improved immensely in recent years), and bond them to the underlying layer in such a way that they wouldn't fall off when hit.

[Brother Oni]

Using diamond for weapons is - only marginally more feasible. There are such things as diamond saws and knives - the saws are hard-wearing, but not particularly sharp, and the knives are extremely sharp, but very brittle. Neither one would be particularly useful as a sword. If you want to know how that might work in practice, take a look at the Aztecs - the obsidian they used for weaponry was not unlike diamond, in that it was very hard and formed a very sharp edge. It worked extremely well for their purposes, but proved completely useless against European metal armour. (And, significantly I think, even the Aztecs never tried to make armour out of obsidian.)

The Aztecs also had obsidian arrow heads which were reported to cause really nasty wounds due to that habit of shattering and fragmenting.

While they wouldn't have been any good for penetrating armour, the Conquistadors didn't go in with full plate harness, so there would have been enough vulnerabilities (or soldiers not in armour), for the arrows to have some use.

[Pie Guy]

The real advantage the conquistadors had was that near everyone hated the Aztecs.

[Gildedragon]

The real advantage the conquistadors had was that near everyone hated the Aztecs.

That and you know... disease.

[Alex12]

If you're looking to make diamond weapons, something like a chainsword from Warhammer 40k might be an option too. If the saw teeth can be removed and replaced, you could make diamond-tipped teeth and it seems like it would be reasonably effective, albeit almost certainly not very practical and phenomenally expensive.

[veti]

The real advantage the conquistadors had was that near everyone hated the Aztecs.

While that's definitely true (and the disease thing, too) - the technological advantage was also important, and armour was the largest single part of that advantage. It's hard to imagine the Aztecs' enemies rallying so strongly behind Cortez, if he and his men had been using technology no better than they themselves already had.

[Jeff the Green]

That and you know... disease.

And the fact that a mounted soldier—let alone a cavalry charge—is freaking terrifying if the closest thing you have to horses is deer (or llamas in South America).

But yeah, like everything else in history, the European conquest of the Americas and the accompanying genocide was really complex and not amenable to either grade-school education or the internet.

[JusticeZero]

Just because it might be overlooked in the talk of macahuitl, it's really easy to get an obsidian blade in daily life. Pick up a glass bottle and break it, presto! Obsidian blades! Obsidian is just naturally occurring glass. You can knap arrowheads from broken glass pretty easily with a bit of patience if you want to, but the properties don't really change much from the base item of "a broken bottle". Glass is very hard stuff, and has a better behavior for making sharp things than other crystals.

[Gildedragon]

Just because it might be overlooked in the talk of macahuitl, it's really easy to get an obsidian blade in daily life. Pick up a glass bottle and break it, presto! Obsidian blades! Obsidian is just naturally occurring glass. You can knap arrowheads from broken glass pretty easily with a bit of patience if you want to, but the properties don't really change much from the base item of "a broken bottle". Glass is very hard stuff, and has a better behavior for making sharp things than other crystals.

All silicates are pretty hard. The nice thing of glass is its amorphousnes, which ties into its lack of strength.
Breaks nicely and along the lines of force, but doesn't have crystal structures to make it sturdy.

A similar thing happens with large crystals, like quartzes (or in this case, diamonds) where a sufficiently large crystal, acts like an amorphous rock when subjected to force (because it doesn't have crystals inside to disperse the forces)

Thus any whack at the rightish sort of angles will pop a crack in your crystal blade.

[Another_Poet]

Jut for kicks, I'll add that when I picture "diamond armor" it isn't a solid piece of armor made out one big diamond. It's like 5,000 diamonds individually placed to overlap like scale mail. Much prettier, much easier to make.

Note that this does not fix any of the breakability problems. Your diamond armor is soon going to be nothing more than Resurrection material components... which you'll be needing anyway.

[Angelalex242]

Of course, a setting like D&D is going to have 'improved' diamonds that don't have all those pesky bitterness problems.

I'm sure there's something on the elemental plane of Earth that functions like diamonds, but isn't brittle in the slightest.

[veti]

Of course, a setting like D&D is going to have 'improved' diamonds that don't have all those pesky bitterness problems.

I'm sure there's something on the elemental plane of Earth that functions like diamonds, but isn't brittle in the slightest.

Ah yes, that would be the king of the plane.

You want to try making him into armour, you're going to have a fight on your hands. Suffice it to say, by the time you're high enough level to do that, you no longer care about the armour anyway.

[JusticeZero]

Of course, a setting like D&D is going to have 'improved' diamonds that don't have all those pesky bitterness problems.

You mean.. steel? Brittle is an inescapable consequence of hard.
Hard isn't even a property that is worth selecting for for the purpose of the items being discussed, at least not as a primary property. You don't want armor to be "hard", you want it to absorb and punishment instead of passing it through to the wearer. Hardness means no absorption, by its very definition. This is why cars are designed with great care to crumple instead of just rigidly holding their shape.