posted
So I'm working on a fantasy world where I need the most common metal to not be iron (magnetic issues). I like the idea of moving down a row on the periodic table to Ruthenium, but I'm worried about the higher melting point.
Iron melts at 2,800 F, but ruthenium doesn't until 4,233 F. Would coal be a viable energy source to produce that much heat without making the ruthenium cost prohibitive? If not, does another fuel spring to mind that might work instead?
I couldn't figure out a Google-friendly way to phrase the question, so even ideas on what phrases might get me an answer would be appreciated.
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posted
What you are looking for is the adiabatic flame temperature of the fuel in air. For coal, that is around 2100°C (3812°F) so no its not hot enough. The only thing I could find that burns hotter than 4233 °F in air is acetylene and even that is only a few hundred degrees hotter.
I should add, that there are much bigger problems with using ruthenium than its melting point. Its twice as dense as Iron anything made from it would be twice as heavy as its iron counterpart. Its also very hard. It would be extremely difficult to machine or even sharpen? Its also very brittle so it could not work for most tools or weapons that require high impact strength. If you are concerned about magnetism, ruthenium is a bad choice from the start since there are a lot of ruthenium compounds with unusual magnetic properties.
Its also difficult to imagine how a planet might come to exist that had much higher levels of ruthenium than iron. Iron is the most stable element in the universe. The processes of nucleosynthesis pretty much guarantee that iron will be more abundant than any heavier element. Copper and bronze are better but its still difficult to imagine any way a planet might have formed that would have more copper and zinc than iron.
If you care about plausibility, select something that is lighter than iron. Aluminum is a reasonable choice.
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posted
The wiki article on smelting is a pretty good start.
The wiki article on ruthenium is also pretty good. Seems it is exceedingly rare, and took until the 19th century to even be discovered.
I'm thinking you're better off going with another non-magnetic metal that is more abundant - such as the aforementioned copper, bronze, or aluminum. Also there are lead, gold, silver, and platinum (though they may be too soft or rare for your purposes).
Of course, depending on your fantasy environment, there are always ways around. Magical fire, for instance, can burn at whatever temperature you like. Elements can be found in different abundances, or useful ones can be concentrated in hostile areas. Magical elements may exist (orichalchum) or certain woods may be used that have increaesd hardness/properties (lignum vitae/ironwood).
posted
The brittleness and extra weight are probably the biggest drawbacks. I basically want something like iron but not magnetic.
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posted
The article on metallurgy seems to think a copper-nickel would be sturdy and non-magnetic. I'll have to find some detail on that.
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posted
What about stainless steel? When nickel is added to the chromium in the steel, it produces a steel that is not magnetic: "Generally referred to as a 300 series, stainless steel that contains nickel is not magnetic at all. The reason is that the presence of the nickel alters the physical structure of the stainless steel and removes or inhibits any magnetic qualities." Link: http://www.wisegeek.com/is-stainless-steel-magnetic.htm
Then of course there is always aluminum.
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posted
Stainless steel could be a great import, but if they can't really work with the iron in the first place, they couldn't have developed it on their own.
Can you harden aluminum enough to build bridges or locks? I suppose the bridges could be mostly stone, but I think that limits who long they can be.
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posted
Folks. This is for a story. It's fiction. If Asimov could put a submarine in a man's bloodstream using the 4th dimension, you can have a world where ruthenium is plentiful. And ruthenium can have any properties the author wants. Or just use handwavium.
My real question is: what magnetic issues make iron unfeasible?
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Iron at room temperature is a Body Centered Cubic (BCC) crystal structure, but when when it's heated red hot (at a temperature lower than the melting point, such as from a coal fire) it switches to a Face Centered Cubic (FCC) crystal structure.
This is important because BCC is much more rigid, while FCC metals are much more maleable. Copper, gold, silver, and aluminum are all FCC at room temperature, making them much more easily bendable than iron/steel is. That's one reason why iron is so great -- you can heat it up to FCC, pound on it with a hammer to shape it how you want, and then cool it down to a BCC that won't budge when you hit it with a hammer.
Titanium doesn't work like this. At room temperature, it has a close-packed hexagonal crystal structure, but when you heat it up, it switches to a BCC structure, the same structure that iron has at room temperature. With iron-age technology, titanium would not be forgeable.
Aluminum could work, except that the chemical reduction method of purifying it is extremely difficult (it used to cost about the same amount as gold by weight). Modern methods are much easier and cheaper, but they require you to already have an industrial infrastructure in place. Pulling an aluminum-based industry up by its bootstraps would be very difficult.
From what you've said so far, I too think that cooper and bronze are going to be your best bet.
What level of technology do you want this planet to have?
posted
I was thinking early Industrial Revolution - the bad guy is testing a threshing machine which would allow many farm laborers to be sent to the infantry and completely change the balance of power in the war with the good guys.
As for the iron, they're fairies. In most fairy myth, they're afraid of iron. I liked the idea that they're more sensative to magnetic fields than us. Iron disrupts that and induces severe claustrophobia in them.
It apparently messes up all sorts of industry to not be able to use iron. They trade with earth cultures, so I may use the invention of stainless steel here as the turning point for their technology. Plus, it would be a cool plot point for them to have jumped from modified Bronze Age to Iron Age in the last hundred years.
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posted
OK, I think bronze would work best as the metallurgical foundation for their technology.
I also like the idea of them eventually being able to create iron alloys that aren't magnetic (as was mentioned earlier, some types of stainless steel, like austenitic stainless, are not magnetic). This would be very dangerous and costly to make, since the the principle ingredient, iron, is a hazardous material, but once it's properly alloyed, it would be completely safe, and stronger and tougher than bronze.
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posted
Bearing in mind that iron would be present, even if it wasn't used. Earth's earliest use of iron was found meteorites, which bypassed the need to refine ores into metallic form. Also, lodestones are natural magnets.
These things would already exist. And your "bad guy" would certainly have fewer qualms about using them.
You could certainly create natural versions of industrial processes. Volcanoes produce glass, after all. And iirc, there is a natural nuclear pile somewhere in Africa. There's no reason why a deposit of iron and nickel couldn't have been heated and alloyed through natural processes in your world.
Actually, isn't the earth's core supposed to be largely iron and nickel? So what mechanism would allow that mixture to become present at the surface?
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posted
Glenn Arnold, I believe you are speaking of the Oklo Uranium Mine in the Gabon Republic of West Africa. I remember reading about it a few decades ago in Scientific American, and it has been featured again more recently in 2009. Link: http://www.scientificamerican.com/article.cfm?id=ancient-nuclear-reactor
Apparently there was an unusually high ratio of U-235 to the more common and non-fissionable U-238, enough so that when it rained and the groundwater provided a moderator to slow down the neutron cascades sufficiently, a low-level fission reaction seems to have taken place, producing a lot of daughter products, and having who knows what effects on plant and animal life on the surface because of the radiation.
As for what mechanism would allow iron and nickel from the core of the earth to rise to the surface, the only one I can think of would be total planetary catastrophe, where the earth is split in two. I think that would require an asteroid the size of Ceres to impact the earth.
Here's something that may be of interest:
quote:Multiwalled carbon nanotubes have the highest tensile strength of any material yet measured, with labs producing them at a tensile strength of 63 GPa, still well below their theoretical limit of 300 GPa.
posted
Card pulled off a world where there was no accessible surface iron except in one particular desert location. Of course, that was in the same universe where people healed injuries through interstellar telepathy, so it wasn't the biggest thing we were asked to swallow.
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quote:Originally posted by Ron Lambert: Apparently there was an unusually high ratio of U-235 to the more common and non-fissionable U-238...
U-238 is fissionable by fast moving neutrons.
That's a matter of definition. Most scientist distinguish between "fissile" elements, those that are capable of a participating in a sustained nuclear chain reaction and "fissionable" element which undergo nuclear fission under any circumstances, but some authors have in restrict the use of the term fissionable to those elements which are also fissile.
At any rate, U 238 is not fissionable by neutrons that are produced by fission of Uranium or Plutonium.
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quote:As for what mechanism would allow iron and nickel from the core of the earth to rise to the surface, the only one I can think of would be total planetary catastrophe, where the earth is split in two. I think that would require an asteroid the size of Ceres to impact the earth.
Earth's moon is thought to have been formed by a similar "catastrophe" with no ill effect that I've noticed personally.
Maybe there's a stainless steel meteorite that was originally part of Earth's core, but which fell back to earth many years after the impact that formed the moon, just waiting to be discovered.
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posted
Actually, that seems tailor-made to have the bad guy actually creating the threshing machine out of iron.
None of the faeries use iron because it is painful to them, induces states of claustrophobia, etc.
He has designed a machine that can be used to send farmers into battle while still gathering grain, but it will only work if it uses iron.
Thus, he essentially forces his subjects to create this machine (essentially torturing them into interacting with the iron) until he has it built...
Or... he may have developed a way to repress or counteract the magnetic field problem in a small way, allowing him to use iron and thus gain an upper hand. This could lend a whole extra dimension to his "bad" nature, and give the "good" guys extra reason to fight (or even extra backgrounds, as they may have been used in the iron process and bear scars, either emotional or physical)
Or... there is another minority race on the planet that he has discovered and subjugated to make his iron machinery (trolls, nymphs, etc?)
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posted
Sean, what I meant was that you cannot make a fission bomb or nuclear reactor out of U-238. When all the U-235 and U-234 have been removed from natural uranium, what is left is U-238. This is called "depleted uranium," and is what is used to make tank-killer bullets (because uranium is so hard and massive, and the U-238 isotope has negligible radioactivity).
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