Bi-Mg Laminates

We demonstrate that Art's Parts, recieved at Coast to Coast Radio, are in fact easy to reproduce with human technology

Public Chat
Similar projects worth following
In April 1996, Art Bell, host of the Coast To Coast radio talk show, recieved samples which were claimed to be from the exterior of a spacecraft that crashed in 1947 between White Sands and Socorro, New Mexico.

Most interesting among the samples was a curious magnesium-bismuth laminate, regarding which many claims have since been made online. Much of these ring true with my experience in metallurgy, but one claim in particular irked me: it was claimed that the material was beyond the capability of humans to replicate - I know this to be false, so with this project, I will demonstrate that.

Magnesium-Bismuth composites could have many practical applications for electrochemistry, radiation shielding, fire protection, photonics, catalysis and Terahertz optics, so it would be beneficial if some methods of their manufacture were more widely known.

This work is licensed under a Creative Commons Attribution 4.0 International License.

Here we will present two methods of making Mg-Bi composites; one mimicking cold spray, and another more analogous to brazing. 

The samples resist delamination about as well as can be expected for laminates with layers of brittle bismuth. Much optimization remains to be done, and I look forward to seeing where people take this! I would be curious to see vacuum brazing of these composites for example, or hydraulic pressing and heating of larger surface areas, or futher optimization of the solvent bath used.

This project features:

  • Chemical process info for coating Bismuth onto magnesium with a reasonably durable bismuth coating (this might also be useful as a primer coating for people experimenting with magnesium electroplating)
  • Preliminary test data of various solvents for the above process
  • Simulated explosion welding apparatus and instructions for solidifying the Mg-Bi composite at room temperature
  • Initial documentation from tests of brazing in ambient environment under pressure

No need for a Github page for this project; the design details are quite simple and straightforward.

As mentioned above, this work is licensed under a Creative Commons Attribution 4.0 International License.

  • 1 × Isopropyl alcohol, 5 mL Ideally drier than azeotropic, Some hydroponics stores sell 99.9% these days. Ethanol or methanol may also work.
  • 1 × Bismuth Chloride, 0.1 gram Can make by burning pepto bismol, then reacting with hydrochloric acid, then drying
  • 1 × Magnesium strips Often sold for lighting fireworks or thermite. Other magnesium alloys may also work
  • 1 × Pliers Any device for compressing the laminate during firing
  • 1 × Blowtorch For heating the laminate to the sintering temperature of the bismuth/creep temperature of the Magnesium.

View all 10 components

  • Impact Tester

    Michael Perrone03/28/2024 at 22:44 0 comments

    Bismuth and magnesium, somewhat like gold and aluminum, are considered dissimilar metals, so heating or melting these materials and expecting a good metallurgical bond isn't the best way to do things. That's where cold spray technology comes in: if you shoot metal powder at a surface fast enough, it can mechanically and chemically bond to the substrate without ever becoming a liquid.

    Image credit to VRC Metal systems

    But cold spray systems cost hundreds of thousands if not millions of dollars to own and operate - so is there something we can do instead? It turns out there is! If you concentrate large amounts of force over a small surface area, you can simulate cold spray or explosion welding

    (more images and details coming shortly)

  • What is the Mg-Bi composite?

    Michael Perrone03/22/2024 at 18:48 2 comments

    Being relatively well-versed in metallurgy and to some extent chemistry, quite a few conventional explanations come to mind when I think of the magnesium-Bismuth composite

    • Firstly, the composite looks like it is produced electrochemically. Magnesium typically forms dendritic or feather-like structures as shown in the above image from Wikipedia during electrolysis of magnesium salts. If I were trying to reduce the formation of these dendrites in a battery for example, I might add some bismuth layers to redirect crystal growth and reduce dendrite formation, which could otherwise short out the battery. Supporting this argument, bismuth is often considered as an additive in magnesium batteries in many scientific articles to promote catalytic activity, provide reversible passivation, and improve magnesium battery efficiency and life cycle. [1], [2], [3], [4], [5]. It is certainly not beyond imagination (though it would require a water soluble bismuth salt that does not electrolyze easily, which is odd) that a magnesium-ion battery could have developed bismuth-magnesium layering during successive charge-discharge cycles, especially when considering article 3. And one could imagine such a prototype battery being used in 1947 by either the US or the USSR.
    • Alternatively, the bismuth lamination may be a prototypical form of anticorrosion coating, of the type actively being developed by Modumetal for more standard industrial metals and alloys like steel. In these materials, the bismuth layer might act as a chemically passive layer to potentially impede corrosion, but considering the galvanic interaction between the bismuth and magnesium, I'm not certain how well that would work unless the bismuth coating is largely free of holes - which could be challenging given what I've seen with magnesium electroplating... 
    • If Bismuth improves the catalytic activity of the magnesium, one could imagine a magnesium extractive metallurgical process utilizing bismuth in some way, occasionally replenished, in the electrolytic bath, to reduce the energy required for electrochemical production of magnesium metal. The stripes could indicate this occasional introduction of bismuth salts into the plating bath. Alternatively, the bismuth could be used to make sure the magnesium easily flakes off of the plating electrode when plating is complete, or again to prevent the formation of magnesium dendrites so that the magnesium extraction bath can run for longer between batches.

    But let's assume for a second that perhaps the composite was damaged by re-entry, weaponry or the crash-landing so it is not in its pristine state. It's certainly possible that the outermost Bismuth layer could have evaporated off in that scenario, and the magnesium could have been scarred in the way shown. What else might it be then?

    • Such a laminate could possibly impede magnesium combustion, which could be a very useful property in aerospace applications. I certainly noticed some protection going on when blowtorching some of the samples - the bismuth would oxidize when the magnesium would normally burn, inhibiting ignition somehow, despite forming what I imagine would be a thermitic composite. With bismuth having such a low melting point, I'm not sure how well this would work in practice: I would expect delamination at high temperatures when the bismuth melts.
    • Having personally played around with magnesium and bismuth electrochemistry in the past, I can attest that thin layers of bismuth on magnesium appear black, even if they are quite smooth (although perhaps the roughness was too small for my equipment to resolve) - so something interesting may be going on with optical absorption at the surface. Perhaps the composite indeed exhibits some interesting infrared and terahertz optical properties, as claimed online.
    • If the material happens to be a terahertz or phononic waveguide, it is possible that the material is also an exotic fuel or power source, considering that Peter Hagelstein's...
    Read more »

View all 2 project logs

  • 1
    Prepare the Solvent Bath

    To make the bismuth coating solution for the magnesium

    Mix about 0.07 grams of BiCl3 with about 5 ml of isopropyl alcohol. This is past the solubility limit, but the excess helps replenish the solution as the magnesium reacts. The drier the alcohol, the better. I used 99.9% isopropyl from the hydroponics store. I haven't tried it with alcohol azeotropes yet, but it might still work.

    You In case you have any trouble finding it, you can make BiCl3 from pepto bismol or similar products by:

    1. Burning the material to get bismuth oxide. This will typically contain impurities of cacium and magnesium oxides, sulfates or carbonates
    2. Dissolving the material with HCl, then precipitating bismuth oxychloride by neutralizing with NaOH. The magnesium and calcium salts will stay dissolved, while the bismuth precipitates.
    3. Filtering and rinsing the bismuth oxychloride, or letting it settle and decanting the water, replacing with DI water a few times.
    4. Once you have rinsed and dried BiOCl, re-dissolve it in as little as possible concentrated HCl, then evaporate off the resulting water and you have your clean BiCl3.

    You could in principle dissolve bismuth with HCl directly, but I found that even with powdered

  • 2
    Prepare the magnesium
    1. Make sure your magnesium surface is fresh and minimally oxidized. If necessary, sand the surface, but make sure to use a fine grit so that the magnesium surfaces are not too uneven to bond. Be very careful with magnesium dust! For tiny amounts it is probably fine to throw it in water to be oxidized, but if you have a lot of magnesium powder, that can be quite dangerous.
    2. Isopropyl alcohol should remove all oils from the surface, but best to use gloves and avoid solvents like limonene, which can inhibit attack by bismuth chloride.
  • 3
    Soak the magnesium
    1. Place your prepared magnesium pieces in the isopropyl alcohol bath to soak. you may want to stir or manually agitate the pieces to help ensure an even coating. We generally let the pieces soak for about 30 seconds - longer and the bismuth can get too thick and flaky to adhere.

View all 4 instructions

Enjoy this project?



Brian wrote 03/29/2024 at 00:33 point

Also, since you mentioned Terahertz, the structure reminds me of a Bragg reflector, composed of alternating layers of different refractive index material. Bragg reflectors can even be used for X-Ray reflection. They are common in laser and fiber optic applications, and most high reflector (non-metal) mirrors work this way.

  Are you sure? yes | no

Michael Perrone wrote 04/16/2024 at 19:32 point

Good idea; yes it's something we had considered - that might be an additional means of radiation shielding, if it was originally used for that purpose.

  Are you sure? yes | no

Brian wrote 03/29/2024 at 00:15 point

Awesome project! This made me think about the superconductivity and Quantum oscillations seen in Bismuth thin films and nano-wires. 

Physical vapor deposition would be another way to create these layered structures. Bismuth is really easy to deposit. It can be done at home with a big bell jar or some other vacuum vessel, and a high quality vacuum pump. Super low pressures are not needed (no turbo pump required). Magnesium is more difficult though, and usually requires magnetron sputtering (not the kind of magnetron used in a microwave oven).

  Are you sure? yes | no

Michael Perrone wrote 03/29/2024 at 02:51 point

Supposedly people have tried PVD on magnesium and they get poor interlayer adhesion between the Mg and Bi - something about extreme surface energy and lattice mismatch? In general, electrochemical processes and mechanical processes should be expected to provide the best interlayer bonding for these materials.

  Are you sure? yes | no

Brian wrote 03/29/2024 at 03:27 point

Bismuth is a difficult material, but is my personal favorite element. It has some unusual electromagnetic properties, and grows beautiful crystals. The first commercial Hall effect sensors were based on Bismuth thin films.

Bismuth is strongly diamagnetic, as opposed to Magnesium, which is para-magnetic. Perhaps this layering of magnetic properties is critical to the design of this structure?

Thermal expansion coefficients alone would cause them to de-laminate, but if some intermingling of the two materials is allowed, then they are locked together. For example- with explosive welding, you can bond aluminum to steel, because they have finger-like interlocking structures that keep them together. 

So, as you mentioned, electrolytic deposition may give the best result, as you can (forcefully) overcome the difference in electronegativity of the two metals and create a better bond.

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates