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Easy-to-Make Material Scratches Diamond
holy_calamity writes "A material tough enough to scratch diamond that can be made without resorting to massive pressure has been developed at UCLA. A regular furnace and a zap of current is enough to meld boron with the metal rhenium." Sound familiar? This is the other new material tougher than diamond, but no word yet on how they rate against each other.
The old material was stiffer, not harder, than diamond. It could still be scratched by diamond.
Military ammo usually lacks quality (b) because it's better to disable an enemy soldier than to kill him, both for the psychological effect at the enemy, who has to watch him suffer; and because his buddies will be busy rescuing him instead of fighting. Oh, and because the Geneva convention says so, they seem to think it's somehow more "humane" to cripple soldiers than to kill them.
God, I wish this dumb myth would die.
First: there is no infantry weapons system (other than the "NLW" which are designed for crowd control, not combat) specifically intended to cripple rather than kill an enemy. One shot, one kill, is always the infantryman's goal. The best possible way to remove an enemy soldier from the fight is to kill him; wounded enemies often can and do keep shooting back. The "wounding is better than killing" meme is often repeated among soldiers as well as civilians, but it does not appear anywhere in Army doctrine.
Second: the LOAC's prohibition on "dum-dum" rounds is basically intended to make things easier on military surgeons; it's a matter of what's humane off the battlefield, not on it.
Third: FMJ rounds, as opposed to the wide variety of other types of rounds which would be acceptable under the LOAC, are used primarily for reliability and versatility. Reliability, because rounds with any exposed lead will foul a rifle under typical infantry combat conditions (dirt, mud, sand, and enormous volume of fire between cleanings.) Versatility, because softer rounds are better for use against unarmored human targets, but that's about it. Trying to stop a vehicle with soft-nose rounds? Good luck. And modern body armor is very very good, but you've still got a good chance of getting through it with a dead-on shot from a rifle of decent caliber if you're using FMJ; soft-nose will just go splat.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Rhenium costs £6.50 per gram if you want to buy it on ebay; boron is £13.50 a gram on ebay because the one seller there is selling an exotic crystalline form. [ebay search for 'rhenium metal' or 'boron element']
a mond_powder_price_list.html will sell you twenty grams (a hundred carats) of half-micron diamond dust for fifty dollars which is a lot cheaper than either the rhenium or the boron.
a sp suggests that bulk rhenium is $3000 per pound, which is a bit over half the ebay price above; some sites, I think mostly run by gold bugs, suggest $6000 per troy ounce, so either there's an opportunity for arbitrage, or they've confused rhenium and rhodium.
So making ReB2 using source materials bought in small quantities on ebay would be about ten pounds (about twenty dollars) a gram; probably the cost of the electricity to run the furnace would be more than that, and the depreciation on the furnace more still.
I paid ten Euros (about fifteen dollars) for the diamond sample I have, which is two milligrams, and various diamond-industry sites give prices on the order of a hundred thousand dollars per gram; of course, rather like microchips, diamond pricing is exponential in the size because you have to find one big diamond rather than gluing two small ones together.
But ReB2 will be competing with diamond abrasive, and http://www.diamondtech.com/products/categories/di
http://www.metalprices.com/FreeSite/metals/re/re.
The not-so-trustworthy-looking http://biotsavart.tripod.com/bmt.htm has boron at about $5000 per kilogram, so $2200 per pound; still these are orders of magnitude cheaper than diamond.