SEM Wire Characterisation

This is Mathieu from Europe. I have interesting pictures to share with you all (with agreement of Pr.Celani).

I had the opportunity to use an SEM (scanning electron microscope) to look at the wires that Pr. Celani sent to us. The pictures are intentionally NOT downsized for you to have close look on them. If you can use a wide screen display and open your browser in fullscreen, you will surely enjoy the following.

Sample preparation is very simple since Francesco always detaches one end of the wire before sending it. We had to reduce its length on the treated side, where it looks greyer.

Light microscope revealed that the surface cracks under mechanical stress. Instead of only studying the surface of the wire we bend it to induce cracks on the surface and open cross sections.

The first picture shows the edge of one crack. We can see how the mechanical stress pealed a tick layer of matter from the surface of the wire. We suspect that this layer is the active material used during the experiment to host the hydrogen and generate the effect.

The second picture shows the edge of this crack. Without it, we are able to see the cross section of this "coating". On the right side some fluffy material sticked to the surface of the core. The core is also very interesting to watch, its roughness is very different compared to the surface. It is dramatically different in organisation like we can expect from an alloy metal.

Taking a closeup on the cross section, we are able to see how this matter is organised.

The coating is measured using a microscope tool just after the picture is taken. This measurement gives us a value of 16µm of the total thickness of the coating. Be aware that this measurement is not very accurate since the section measured is not parallel to the plane of the picture. But it gives you a range of value.

On the surface we have big grains of metal their depth is 6.6µm under the surface of the coating. We measured one grain that crystallised on the surface and is approximately 11.6µm. Again, this grain might not be representative of the rest of the surface.

The following picture is showing the diameter of the wire with and without the coating. Now we can have a better range of value for the thickness of the coating. We can say that it is more than 20µm thick. Knowing that Celani is starting with a 200µm constantan wire, the treatment is expanding its external surface by an order of two. This is not surprising knowing that Defkalion is talking about super expanded nickel structures as well as Celani does.

We can also see that the coating detaches itself from the core of the wire.

Here we are looking at a detached part of the coating. We can see on the right side that there is a piece of the core of the wire that was about to detach. This gives an indication of how fasten the coating and the core are together without mechanical stress. This is very likely that the coating and the core are expanding at different ration under increasing heat, squeezing or making room for what is in the between.

But let's get to the last one.

This by far, the most interesting SEM picture. It shows a closeup of the internal surface of the coating.

The coating is made of superposed layers melted one by one uniformly at high temperature because each layer is uniform in surface shape until we get to another. This definitively looks to me like a high temperature treatment followed by a quenching, because the the layers didn't have time to crystallize, they kept a melted look. The inside looks smooth where the core is definitively rougher. We can notice a lower layer (closest to the core) because it detached and cracked from both the core other layers at the center of the picture. We can barely see the next one on the edge, at the bottom of the picture.

The lowest layer is thick it looks to be in the range of 1 to 2µm, however the other ones looks dramatically thiner, around 500nm or even less as it piles up.

So what can we summarise from this study:

• The wire is composed of a core and a coating,
• it is easily detachable from the surface,
• the coating is made of superposed layers, which confirms Celani's claim,
• the coating is at least 20µm thick,
• it is in the range nanomaterial for the external layers, micromaterial for the internal layers of the coating.
• we have big grains on the surface and disorganised metal in the core.
• it looks amazing! (completely personal judgment ;)

That's all for today folks. More to come soon, as I have the EDS-X (energy dispersive spectroscopy X-ray) spectrum in my hands.

And don't miss tomorrow, BIG TIME!