Display MoreMy initial report on the Ni mesh preparation:
This is a "Live Document" and will be updated periodically as the work continues.
AlanG
Great work 👍
Display MoreMy initial report on the Ni mesh preparation:
This is a "Live Document" and will be updated periodically as the work continues.
AlanG
Great work 👍
Are there any diagrams of Mizuno's vacuum system? I see that there is just one port leading to the roughing pump and the turbo molecular pump (TMP). I've read that TMP are supposed to have a very wide connection to the vacuum chamber, but I guess he found that this is good enough.
I'm curious what the plumbing looks like for stepping down the wide mouth of the TMP to the small tube, and what plumbing is used to connect both pumps to the same tube.
Great work Alan, always great since parkhomov's epic time you already shared.
You seem to follow Dr Mizuno's exact process as well described by JR.
I ask myself about relevance (for future XH) between this method VS the plating one which seems, according to Mizuno, to give same results !?
i will try from my side to clean first Ni mesh by ionic etching then i'll sputtering, we could confront.
Display MoreMy initial report on the Ni mesh preparation:
This is a "Live Document" and will be updated periodically as the work continues.
AlanG
My initial report on the Ni mesh preparation:
Excellent Alan. You obviously have access to some hot kit.
I did a CAD drawing a few days ago to get my head around the situation with preparation. Perhaps someone could help me. I have read the papers published, but can't for the life of me find where it says the mesh is a double spaced weave. I did it single both ways and then a few calcs., for numbers of sites and likely thickness of Pd.
Also, re the CaCO3 crystals, I wonder if these are more likely to be swept away by the physical application galling technique, rather than included in the bonding. I say this because I reckoned that one reason for the better performance of the rub method is that it physically wipes away any oxide that will have formed over the Ni mesh after cleaning. Ni gains its anti-oxidation properties from its formation of an instant cover of oxide, even if it looks clean and has just been "cleaned". This gives it a passivation layer which soon gets thick enough to prevent further oxidation. It could be removed by the low pH of an electroless plating solution, but these are all difficult mechanisms to quantify. Any oxide on the uncovered surface of the mesh would likely be reduced and evolved as water in the bake out with D2 present.
I understand conflats with copper gaskets. This is an impressive metal to metal seal suitable for ultra high vacuum.
1) It makes me wonder how a simple threaded hole in the side of a chamber works. Is it leak tight to 0.01 Pa?
2) Are the swagelok values that Mizuno used, infinitely reusable? Or are they single use like the conflat copper gaskets?
3) Are gas feed throughs like this one meant to be welded on?
1) It makes me wonder how a simple threaded hole in the side of a chamber works. Is it leak tight to 0.01 Pa?
Very unlikely...
Display MoreMy initial report on the Ni mesh preparation:
This is a "Live Document" and will be updated periodically as the work continues.
AlanG
"This suggests that the formation of CaCO3 crystals is a functional part of the treatment." Jesus Christ! This is most unexpected!!!
...
3) Are gas feed throughs like this one meant to be welded on?
Contact LDS Vacuum with any questions: Phone (407)862-4643 via Fax (407)862-8723 or [email protected] |
Perhaps you have already reached out to the vendor?
I am getting conflicting messages. Some say they can not proceed unless more info is made available. Others appear to have enough (info) to proceed on with their attempted replication.
So which is it?
I could proceed using the information at present. It might be a replication in the sense of a replication of the effect. It likely would be other than a twin of Mizuno's R20. To my mind the goal is replication of the effect. I understand why some might reason that a twin reactor is a good way to proceed.
Shane D. Where do these conflicting messages come from?
Here is a vacuum system diagram involving a chamber, roughing pump, and turbomolecular pump:
Problem:
Mizuno apparently has just one vacuum system line coming out the endcap, next to the heater feedthrough. This is different from the standard situation where the turbomolecular pump is attached directly to the chamber.
The diagram below is a possible solution. Is it correct?
If you have the $$ you might just want to get a TMP system such as the Leybold Turbolab so that it has all the connections, roughing pump, controller, systems to turn off the TMP until the roughing pump pulls a fair vac, and so on. https://www.idealvac.com/Turbo…ms-NEW/pl/1363-44-232-414
The Turbolab is too expensive for me. In fact, I might just try to get a used Alcatel that goes down to 0.1 Pa or 0.01 Pa, without a turbomolecular pump. Simpler also.
I suggest you get inspired by what JR says, just get inspired, then trust your engineering skills.
I also think that a simple second-hand pump should be enough, main things aren't there, i think.
The 2 most important things would be to do are :
remove oxide before Pd deposit,
respect the 3W / cm2 for heater you should use.
The Turbolab is too expensive for me. In fact, I might just try to get a used Alcatel that goes down to 0.1 Pa or 0.01 Pa, without a turbomolecular pump. Simpler also.
I am getting conflicting messages. Some say they can not proceed unless more info is made available. Others appear to have enough (info) to proceed on with their attempted replication.
So which is it?
I don't think it's either Shane, it's just the spectrum of differing levels of knowledge, experience, approach, aspiration and all the other human qualities that you get when a bunch of individuals come into contact with the aim of doing something.
Yesterday, I was surprised to learn from AlanG that the mesh he received from the "Mizuno source" was a double weave. I'm stuffed if I can find where, in the papers I have, that it states it is made this way. I had done some CAD drawings to get an appreciation for the physical nature of the application and the reaction sites. I did it as normal single weave. Now you could say that isn't going to make a quantum difference. However, the point seems to have been made by Jed and others that we need to replicate in as much detail as possibe, the Mizuno experiment. It looks like yet another dichotomy to me, so make of it what you will. I've got 30 years experience in freelance technical development, and, motivated believer though I am, I'm not happy to proceed until much more attention gets paid to detailed information. There are too many unanswered questions. Proceed and hope isn't an approach I apply to projects.
But then, of course, you could apply Cydonia's perfectly valid approach of "get inspired, and trust your engineering skills". That is though, of course, if you have confidence in them to get past the details and hope that none of them is the one that you miss and which turns out to be crucial. Another of these was again pointed out by AlanG's discovery of the presence of CaCO3 crystals due to washing with tap water. This could be purely incidental, or a vital catalyst.
At this point I would like to make it clear that my issue is not with lack of explanations of mechanisms- we know we are in the dark on that front- it's the possible missing of detail of exactly what TM has done that could cause the missing of something unknown, but vital. This may well lead to failure, and loss of faith in the results of TM. Then there is the potential charge of deliberate failure, and all the rest of it. It's a tricky one to call.
The Mizuno mesh is 'twill weave' I'm pretty sure that makes little difference. The critical thing is always 'process knowledge. When you have done a lot of lab work you learn to 'fill in the gaps' in descriptions of a method. But, you can never be sure you filled them in in the right way when attempting a close replication.
The Turbolab is too expensive for me. In fact, I might just try to get a used Alcatel that goes down to 0.1 Pa or 0.01 Pa, without a turbomolecular pump. Simpler also.
Hello Arun, if you can’t do an exact replication, you then call your experiment an “analogue” and document it as well as Mizuno/Rothwell did, with emphasis in the differences. We don’t know what is te key factor in Mizuno’s succes, we suspect it was the position of the heater, but also the low pressure might play a role. Try to be as exact in duplicating the reported conditions as you can, and if it does not work, and you document the differences of your analogue, then we all learn something valuable.
Hello Arun, if you can’t do an exact replication, you then call your experiment an “analogue” and document it as well as Mizuno/Rothwell did, with emphasis in the differences. We don’t know what is te key factor in Mizuno’s succes, we suspect it was the position of the heater, but also the low pressure might play a role. Try to be as exact in duplicating the reported conditions as you can, and if it does not work, and you document the differences of your analogue, then we all learn something valuable.
Agreed, certainly.
Was Mizuno using AC or DC?
Can anyone recommend a cheap power supply that runs on 110V and goes up to 500W?
I am getting conflicting messages. Some say they can not proceed unless more info is made available. Others appear to have enough (info) to proceed on with their attempted replication.
So which is it?
I am on the edge of deciding either way. If I were really convinced, I would plan on making six units and order that expensive Turbomolecular Combo sited above. As it is, I have ordered enough second-hand equipment and supplies to give it a try. If the second-hand pump doesn't work I will either try to rebuild it myself from a kit or send it in to have someone else rebuild it. I want to look at the Pd on the mesh with a microscope and see how it looks. If more information were available, I would be more enthusiastic. If the picture of Mizuno's unit in front of the fireplace were plugged in and had Bob Greenyer warming his back while giving two thumbs up, that would cause me to become more excited.