Metallic Hydrogen created, will change spaceflight

[DerekL1963]

  On 2/10/2017 at 9:18 PM, Steel said:

However, since high temperature (i.e abouve 200 K) metastable metallic hydrogen would likely be a room temperature superconductor, it would also likely be the most valuable thing on earth and so cost prohibitive to just use as shielding.

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That depends entirely on how much it costs to manufacture in quantity.

[Steel]

  On 2/10/2017 at 10:31 PM, DerekL1963 said:

That depends entirely on how much it costs to manufacture in quantity.

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I'll put it this way:

It's a material that so far we've only (supposedly) made in minuscule quantities at pressures above 1,000,000 atmospheres in a diamond vice. If it a) exists and b) is in fact metastable it's likely that it's a room temperature superconductor and so literally every defense company, electronics manufacturer and pretty much everyone else will want it, including every material science research lab in the world. A room temperature superconductor would be so beneficial to so many aspects of our world today that using it as radiation shielding is just an enormous waste (and not just of money)

Edited February 10, 2017 by Steel

[DerekL1963]

  On 2/10/2017 at 10:46 PM, Steel said:

I'll put it this way:

It's a material that so far we've only (supposedly) made in minuscule quantities at pressures above 1,000,000 atmospheres in a diamond vice. If it a) exists and b) is in fact metastable it's likely that it's a room temperature superconductor and so literally every defense company, electronics manufacturer and pretty much everyone else will want it, including every material science research lab in the world. A room temperature superconductor would be so beneficial to so many aspects of our world today that using it as radiation shielding is just an enormous waste (and not just of money)

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No matter how many ways you put it, whether or not it's a waste depends on the quantities in can be manufactured in and the cost of manufacture.  Period.

[wumpus]

  On 2/11/2017 at 12:12 AM, DerekL1963 said:

No matter how many ways you put it, whether or not it's a waste depends on the quantities in can be manufactured in and the cost of manufacture.  Period.

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While hydrogen might not be efficient to manufacture as a [transport] fuel, it is absolutely abundant relative to any scheme of obtaining metalic hydrogen.  Unless there is some limiting factor in making a diamond press (certainly it might take some time to scale up diamond press manufacture by several orders of magnitude), it would be hard to "waste" metalic hydrogen.

[DDE]

  On 2/10/2017 at 10:46 PM, Steel said:

A room temperature superconductor would be so beneficial to so many aspects of our world today

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Citation needed

[Steel]

  On 2/11/2017 at 5:36 PM, wumpus said:

While hydrogen might not be efficient to manufacture as a [transport] fuel, it is absolutely abundant relative to any scheme of obtaining metalic hydrogen.  Unless there is some limiting factor in making a diamond press (certainly it might take some time to scale up diamond press manufacture by several orders of magnitude), it would be hard to "waste" metalic hydrogen.

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The limiting factor would likely be the ability to make large scale flawless diamonds

[wumpus]

  On 2/12/2017 at 10:16 AM, Steel said:

The limiting factor would likely be the ability to make large scale flawless diamonds

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That and how long they last while making the stuff.

[TopHeavy11]

From what I've heard, M.H. could have quite the range of uses. I know Scott did a video on this, but what do you think of M.H. and it's uses?

[Val]

Merged 2 threads and removed a post referring to this thread.

[p1t1o]

So apparently the diamond vice cracked and the sample disappeared - so much for remaining stable.

And whether or not they had actually succeeded in creating a metallic phase is also now in question.

 

http://www.sciencealert.com/the-world-s-only-metallic-hydrogen-sample-has-disappeared

https://arxiv.org/ftp/arxiv/papers/1702/1702.04246.pdf

https://arxiv.org/ftp/arxiv/papers/1702/1702.05125.pdf

 

[DerekL1963]

  On 2/28/2017 at 8:48 AM, p1t1o said:

So apparently the diamond vice cracked and the sample disappeared - so much for remaining stable.

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Well, even if it is stable (or metastable) - the sample is microscopic in size and thus pretty hard to find among the debris

[Steel]

  On 2/28/2017 at 8:48 AM, p1t1o said:

So apparently the diamond vice cracked and the sample disappeared - so much for remaining stable.

And whether or not they had actually succeeded in creating a metallic phase is also now in question.

 

http://www.sciencealert.com/the-world-s-only-metallic-hydrogen-sample-has-disappeared

https://arxiv.org/ftp/arxiv/papers/1702/1702.04246.pdf

https://arxiv.org/ftp/arxiv/papers/1702/1702.05125.pdf

 

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Yeah there was a reasonably large sentiment, even at the first announcement that they might not have actually made metallic hydrogen, but instead the change in reflectivity they saw had something to do with the material (I can't remember off the top of my head what it was) that they used to coat the diamonds

[Wjolcz]

  On 2/28/2017 at 5:28 PM, Steel said:

Yeah there was a reasonably large sentiment, even at the first announcement that they might not have actually made metallic hydrogen, but instead the change in reflectivity they saw had something to do with the material (I can't remember off the top of my head what it was) that they used to coat the diamonds

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Aluminium?

[Steel]

  On 2/28/2017 at 5:58 PM, Veeltch said:

Aluminium?

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Sounds about right!

[p1t1o]

  On 2/28/2017 at 5:28 PM, Steel said:

Yeah there was a reasonably large sentiment, even at the first announcement that they might not have actually made metallic hydrogen, but instead the change in reflectivity they saw had something to do with the material (I can't remember off the top of my head what it was) that they used to coat the diamonds

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  On 2/28/2017 at 5:58 PM, Veeltch said:

Aluminium?

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  On 2/28/2017 at 6:02 PM, Steel said:

Sounds about right!

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Its not that. The diamonds were not coated - it would make it hard to see what they were trying to study. It would also be a contaminant, if you are trying to observe hydrogen in a unique environment, you dont want another substance in there that might also undergo a weird change, you wouldn't know what you were seeing - its hard enough with a single known substance.

When they compressed their sample of hydrogen, first they observed it going from clear to black as one transition was reached (I forget the specifics) and as pressure was increased, it turned reflective. This is/was thought to signal the creation of a metallic phase.

I think the hoo-haa now is because another team has come along and said that there are phases of hydrogen that are reflective that are not metallic, thus throwing doubt on the initial conclusion. I think.

 

  On 2/28/2017 at 5:13 PM, DerekL1963 said:

Well, even if it is stable (or metastable) - the sample is microscopic in size and thus pretty hard to find among the debris

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lol are you suggesting its lying around somewhere still in the lab with folks in white coats on their hands+knees looking really hard at the floor

You know, I cant refute that, that could be happening.

Edited February 28, 2017 by p1t1o

[Steel]

  On 2/28/2017 at 6:50 PM, p1t1o said:

Its not that. The diamonds were not coated ...

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They actually were (albeit with alumina not aluminium). From the paper itself:

"We coated the diamonds along with the mounted rhenium gasket with a 50 nm thick layer of amorphous alumina by the process of atomic layer deposition"

[DerekL1963]

  On 2/28/2017 at 6:50 PM, p1t1o said:

You know, I cant refute that, that could be happening.

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It's improbable, but not impossible - we simply know nothing about the substance created.  (Presuming that contrary to the critics something actually was created.)

[p1t1o]

  On 2/28/2017 at 6:55 PM, Steel said:

They actually were (albeit with alumina not aluminium). From the paper itself:

"We coated the diamonds along with the mounted rhenium gasket with a 50 nm thick layer of amorphous alumina by the process of atomic layer deposition"

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Well thats me wrong again  that'll teach me to skip reading a paper...

Though that equates to a coating of a glass, which I presume is nice and see-through, compared to aluminium metal. From a quick google around hte process it looks to be an abrasion protection layer. Weird since its diamond, perhaps its less permeable to hydrogen.

*edit**

You know, I really need to spend the half hour or so to digest these things before shooting my mouth off...

"First, there are questions about the experimental arrangement. The author should prove that the
observed reflection is from the hydrogen sample and experimentally exclude a possibility of reflection from
the layer of alumina at the surface of diamond anvil. Amorphous alumina has a band of 3 eV (Århammar,
et al. 2011) and it might be closed at very high pressures. Other materials for coating should be used to
exclude a possibility of reflection from alumina which might react with hydrogen at very high pressures.
Reaction of hydrogen with the surface of diamond at megabar pressures is also possible (Liu, Naumov et
al. 2016) and should be taken into consideration."

So looks like you were right @Steel, reflection from the deposited alumina is a possibility, even if they havn't resolved it yet. 

Edited March 1, 2017 by p1t1o
Nothing like a good bash to the ego

[YNM]

So, bad news ? Metallic Hydrogen isn't real yet ?

[p1t1o]

  On 3/1/2017 at 3:47 PM, YNM said:

So, bad news ? Metallic Hydrogen isn't real yet ?

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I think its a "don't know", but if it makes you feel any better, I think thats where we were from the get-go.

[YNM]

Well, I don't feel better... Just that apparently this is really cracking people's nerves. I feel bad for them, but hey, science is meant to ensure we don't fool ourselves - better tools next time !

Edited March 1, 2017 by YNM