Chapter 531 It's Better to Torment Others than to Torment Yourself

If counting the number of failures, Hou Jinli couldn't count how many times he failed.

At first, when he was only preparing SG-1 materials in the laboratory, he was attracted by the waste that was accidentally produced by the experiment.

Compared with ordinary graphite materials, the feel of that waste material is really special.

All of the above are conclusions drawn from his experience accumulated in experiments, and finally in a systematic study, he discovered that the reason why this waste is special is that it is willing to condense with a layer of porous network on its surface. Airgel compartment.

To be honest, this result somewhat disappointed him. After all, the porous network airgel made of graphene is not a novel research result, and it can even be said that similar materials have been used in some electrode materials.

However, as it was the first time in his life that he independently applied for a research project, and it was also the first project he applied for after coming to this institute, he did not want to give up so simply.

So when he found that the porous network airgel itself had no special value, he continued to conduct research on its performance in other dispersion media and dispersed phases, as well as the properties exhibited by its composite with other materials. study in depth.

The process is hopeless.

He was even so desperate that he doubted his life.

Fortunately, the last time, he did not give up.

Using this porous network airgel prepared from graphene as a toughening agent combined with silicon carbide ceramics has played an unexpected miraculous effect!

As a toughening agent by itself, the porous network airgel is not superior, at least compared to other similar materials.

However, its performance in terms of thermal performance made him so excited that he couldn't help shouting out in the laboratory.

Unable to wait to write the experimental results into a report, Hou Jinli handed it over to the institute.

Without too many twists and turns, the experimental report was placed on Lu Zhou's desk the day after he handed it in...

...

Although many interesting inventions are born by accident, this accident is too unexpected.

Looking at the experiment report in his hand, Lu Zhou showed interest on his face.

"interesting."

The content of the report is divided into two parts.

The first part is about the preparation of this porous network airgel.

Choose graphene oxide as the basic raw material, prepare 1-2 mg/ml graphene oxide solution, add reducing agent, then stir for 5-10 minutes, let it reduce at 90-160°C for 30-45 minutes, take it out immediately and put it in the freezer Freeze for 4 hours, take it out and thaw it, and continue to restore it at high temperature for 5 hours, and finally wash it with water several times and dry it... Then you can get this porous network airgel.

As for the second part, it is the key content of the whole experiment.

In the experiment, through the process of atomic layer deposition, Hou Jinli's research team chemically bonded the porous network airgel made of graphene material to the SIC ceramic layer, and thus obtained a graphene with special structure - Ceramic composite materials.

From the perspective of microstructure, this material can be abstracted into a honeycomb-shaped graphene layer connected in the middle of the ceramic layer, and these honeycomb-shaped graphene molecules are tightly bonded to SiC molecules.

According to the experimental results obtained from the high temperature resistance test, in an oxygen-free environment, this special graphene-ceramic composite material can withstand a high temperature of 3200 degrees!

And, not only its excellent high temperature resistance, this material has a small coefficient of thermal expansion, and has significant anisotropy in thermal conductivity.

That is, thermal energy is easy to transfer along the cross-sectional direction, but not easy to transfer in the vertical cross-sectional direction!

In addition, including tensile strength and compressive strength, as well as resistance to thermal stress and so on.

Judging from these data, this material can be said to be quite outstanding.

Seeing the interested look on Lu Zhou's face, Yang Xu asked, "Is this the kind of material you need?"

"It's hard to say." Putting down the experimental report in his hand, Lu Zhou leaned on the office chair, "But this report has provided me with a way of thinking."

Yang Xu: "Thoughts?"

"That's right," Lu Zhou nodded, and after thinking for a moment, he continued, "At first I subjectively thought that ceramic materials were not suitable for the first wall because of its poor heat dissipation performance, but from another perspective, This kind of heat transfer performance perpendicular to the interface is better if it is smaller."

Yang Xu: "Why do you say that?"

"Because of the liquid lithium neutron recovery system," Lu Zhou smiled, and continued, "With the thermal conductivity of carbon fiber composite materials, we have to consider adding a heat insulation layer between the carbon fiber composite material and liquid lithium, otherwise 3000 If the working temperature is above 100 degrees Celsius, the liquid lithium layer we use to recover neutrons will be vaporized by a little carelessness.”

The difference in operating temperature between the two materials can be said to be one of the core difficulties in the entire reactor engineering.

If the thermal conductivity is too weak, it is not good, and if it is too strong, it is not good. From this point of view, carbon fiber seems to be a bit too much.

In contrast, the anisotropy in thermal properties of this new material is quite prominent. Appropriately weakening the transfer of heat energy in the direction of the vertical section can leave enough buffer time for the external cooling device.

As for the heat dissipation of structural materials, it can also be solved by "inserting heat pipes into the structure and exporting the heat transferred along the cross-sectional direction".

Although he didn't know much about fusion engineering, Lu Zhou's explanation was fairly simple, and Yang Xu immediately understood what he meant.

However, although the thermodynamic problem is basically solved, there is a more critical problem here...

"What about the ability to resist neutron radiation? This is the most critical thing."

Hearing this sentence, Lu Zhou sighed: "You are right, this is the crux of the problem. Although this material is suitable in all aspects, but the ability to resist neutron radiation...whether it works or not depends on You have to try it to find out.”

Whether it is silicon carbide or graphene, the nuclei of carbon and silicon are still very stable, and the C-Si covalent bond is far more stable than the metal bond. At the same time, both materials are also considerably transparent to neutron beams.

However, in theory it is.

But in reality, neutron irradiation damages materials not only by atomic transmutation and internal chemical bonds, but also by the purest physical structure.

For the latter, it is basically useless to rely on theoretical analysis, and only when it is obtained in experiments can conclusions be drawn.

The only trouble is...

There is no way to try this stuff.

Yang Xu smiled bitterly, and said tactfully, "I'm afraid this experiment is not very easy to do."

The test of anti-neutron radiation performance is the most difficult item in materials science, and it is not one of them.

The general anti-irradiation experiments are all good, and neutrons can be released by bombarding the beryllium nucleus with alpha particles.

It can even be said that the most important reason why it is difficult to study the materials of the first wall of a controllable fusion reactor is that there is no equipment that can test the materials for radiation resistance.

Where can I find such experimental equipment for continuously bombarding the sample with 14 MeV neutrons?

General neutron sources simply cannot reach this magnitude.

Even if you go to Daya Bay, the radiation level of the nuclear fission nuclear power plant is two orders of magnitude different from the radiation level of the fusion reaction!

As for the accelerator...

That's even more nonsense, I haven't heard of anyone who can directly accelerate neutrons. If anyone really does it, I'm afraid that the entire theoretical physics community will have to call him Dad.

As for indirect acceleration (deuteron method), there is, but in fact, to obtain the energy of neutrons, it is better to directly shoot alpha particles into beryllium metal foil. The only advantage of the former is that it is slightly more stable in the direction of the neutron beam.

Thinking of this, Lu Zhou also felt a little troubled. He tapped his index finger on the table and weighed in his heart.

Let the STAR device "reluctantly" again?

Not impossible in theory.

But it takes a one-month strike to do an experiment, isn't the price too high?

After all, this stellarator device is currently the only one in China.

The experts of the nuclear industry group are still studying how to imitate it. If the only piece of equipment is broken, it will be a joke.

However, at this moment, a flash of inspiration suddenly appeared in Lu Zhou's mind, and he reached out and patted his forehead.

MMP!

Just thinking about how to toss his stellarator, how could he forget about the tokamak.

Although the pulse ignition is not restricted for a long time, it can still be ignited anyway!

Although there is only one stellarator in China, there are still many tokamak devices...