Chapter 1072 I’ll do it even if it costs me the rest of my life!
Old Duan was very happy. Chief Engineer Gao really did what he said. He said he would solve each problem one by one, and he solved them one by one neatly.

However, Yu Yuncheng knew that there might be many problems with his craftsmanship.

Just now, Chief Engineer Gao indeed found a lot of problems just by looking at the sample inspection report, but there are some problems that cannot be seen just by looking at the report.

"Mr. Gao, how about this? I'll report the entire process to you, and you can give me some pointers?"

Gao Zhendong nodded and said, "Okay, go ahead. I'm actually quite interested in your craftsmanship."

He has patent documents in his hands. There may not be any details, but the general direction is definitely correct. I believe that Yu Yuncheng and others can produce results based on the general direction.

Yu Yuncheng took out the process documents that he had prepared long ago and opened them for Gao Zhendong to see. While flipping through them, he carefully explained the specific operations and parameters of each step, as well as his own ideas when designing the process.

Sure enough, he soon gleaned a lot of details.

"…The best hydrocarbon gas is methane, ethane, or propane, and the carrier gas is nitrogen. The ratio of methane to nitrogen is controlled at 1:2…"

“What is your pre-treatment solution?”

“Ethanol.”

"Change it. Add two things to the pretreatment solution: methyltrichlorosilane, triethanolamine, and ethanol in a ratio of 0.5:1:20. The immersion time of the graphite substrate is from half an hour to 40 minutes."

Gao Zhendong did not explain the reason, and it was difficult for him to explain the reason. Anyway, this is my suggestion, and you just need to do it first.

Yu Yuncheng didn't ask. Chief Engineer Gao thought that he would tell him, and if he didn't tell him, there must be a reason. Just do it first. As for the reason, if the result is ideal, it will be relatively simple to reverse the reason based on the result and the operation method.

"Chief Engineer Gao, is it that simple? Can we get pyrolytic graphite?"

Gao Zhendong nodded: "Yes, this way we can get pyrolytic graphite, but it is not the best pyrolytic graphite, and the degree of orientation is not the highest."

Whether it is Yu Yuncheng or Lao Duan, they will know what Gao Zhendong is talking about when he talks about orientation. This thing requires directional performance, anisotropy. The purpose of high orientation can be understood by just listening to the name.

However, Gao Zhendong's words seemed to give them a shot of adrenaline. Chief Engineer Gao must have some ideas when he said this!
"Chief Engineer Gao, how can we further improve the degree of orientation?" Old Duan was very interested. If Gao Zhendong's guidance just now was mainly focused on the CVD process, and Old Yu was most interested in it and had the most relevant expertise, then what Gao Zhendong was talking about now was closely related to himself.

Anisotropic graphite may have more uses than just these few.

Gao Zhendong pointed in the south and north directions: "Magnetic field, heat treatment annealing!"

To be honest, these two suggestions have confused other comrades.

If the magnetic field can still be barely understood, then annealing, a processing technology that they think is only related to blacksmithing, is really hard to imagine what it has to do with graphite.

Seeing their confused looks, Gao Zhendong smiled and said, "Do you think annealing is totally incompatible with pyrolytic graphite?"

"Yes, yes, we have been working on graphite for so many years, but we have never thought about its relationship with the metallurgical heat treatment technology of your 17th Ministry of Machine Building." Old Duan touched his head. He really couldn't think of this thing.

Not to mention him, even Yu Yuncheng who came from the 17th Ministry of Machinery looked confused. How could this thing be so mastered?

Unexpectedly, Gao Zhendong nodded: "Have you ever thought that heat treatment is actually adjusting the crystal state of metals, and pyrolytic graphite is itself a crystal state of carbon? Heat treatment can have an effect on metals, but the underlying reason is that it works on crystalline substances, so graphite crystals are not crystals?"

That seems to make sense, right?
Although Lao Duan had previously worked with graphite through roasting, he was not completely ignorant of the crystalline state of carbon. Yu Yuncheng was even more familiar with it.

Pulling silicon single crystals also involves heat treatment steps, so for him, this is a relatively easy thing to figure out.

"Then how do we do it specifically? Mr. Gao, do you have any plan?" Old Duan acted as if he didn't want to bother two people with the same thing.

Gao Zhendong said: "You can do a few more tests. The pyrolysis temperature is 1500℃~2000℃. After the pyrolytic graphite sample is deposited to the required thickness, start cooling it down. When it cools down to 700℃~750℃, put the sample into a magnetic field with a magnetic field strength of 100~150 Gauss and a magnetic field frequency of 120~150Hz for magnetic fieldization. When the sample cools down to 100℃~150℃, take it out."

"Is it done?" Lao Duan was a little anxious. It sounded like it wasn't difficult, but the magnetic field strength was a little high, so it took some effort. Fortunately, there was an electromagnet, so it shouldn't be a big problem. At worst, a miracle could be achieved with great force. 100~150 Gauss is about 10~15 millitesla (mT), so it wasn't a big problem.

Yu Yuncheng laughed and said, "It's definitely not over yet. There is no heat treatment step in this step. It's all magnetic, no heat." He is more familiar with this aspect than Lao Duan, so he knew it was not over yet as soon as he heard it.

"Yes, after cooling down to the temperature I just mentioned, you take the sample out of the magnetic field, cut it into appropriate sizes, and place it in a high temperature and high pressure environment with a temperature of 2400℃~3500℃ and a pressure of 10~50MP for heat treatment. Use argon gas protection during the treatment, and the treatment time is 60~120 minutes. This step is the heat treatment annealing."

Gao Zhendong explained it in great detail. Although a certain range was given, the upper and lower limits of the range were very clear. For Yu Yuncheng and others, it was almost a matter of picking the upper and lower limits within these limits, and adding a few typical interval values, so that they could grasp the relevant rules very well, which was a bit like doing an orthogonal experiment.

"Mr. Gao, what kind of product can we get after this process?" Old Duan was really itching to do it. Chief Engineer Gao explained it so clearly, so he should be very clear about the result.

Gao Zhendong thought about it and decided that he really had to give them a clear range. Otherwise, if they got a slightly better result and thought they had succeeded, it would be a waste of the potential of the entire process.

Gotta give them a goal.

"Well... let me put it this way. According to my preliminary theoretical estimate, the difference in thermal conductivity between the two directions is at least a hundred times."

"How much?"*2.

Gao Zhendong's words shocked Yu Yuncheng and Duan Gong. Hundreds of times? At first it sounded like a fantasy. You know, for a certain material, waxworms have an upper limit to their thermal conductivity in one direction. Such a huge difference can only mean one thing.

——That is, the thermal conductivity in another direction is extremely small, almost to the point of being adiabatic!

"More than 100 times!" Gao Zhendong repeated the data again.

"Moreover, the directional properties and other properties of this graphite are very good. I estimate that it can be close to the level of single crystal graphite." Gao Zhendong dropped another big bomb.

"Really?" Old Duan's eyes widened. He had to fix it properly.

Gao Zhendong nodded: "You will know when you try it out. Of course, this is my theoretical analysis. You will know the details only after you try it out, but I estimate that the difference will not be too big."

As for what theory it was based on and how the analysis was done, Gao Zhendong didn't say, and it was difficult for people to ask.

The properties of single-crystal graphite are useful in many places, but it is not easy to prepare. For Lao Duan of Northeast Carbon Research Institute, a polycrystalline graphite that is close to single-crystal graphite is not enough to fully describe no matter how high it is.

"Boss Gao, even if this thing can't be successful in a short time, I, Old Duan, will devote the rest of my life to it and make it happen! I will never let your research go to waste!"

At this time, Duan Gong was much more excited than Yu Yuncheng, who only received suggestions for improving the CVD process and had a deeper understanding of the CVD process.

Gao Zhendong smiled and said, "Not really. If you find any mistakes, it is necessary to adjust the direction in time."

Having said that, he knew very well that he didn't need to spend the rest of his life on this path, as it was already there. After all, the patent documents were not obtained in vain. For Lao Duan and his team, they only needed to get a suitable medium-frequency induction furnace and a magnetic field generator to start the experiment, and the extremely detailed preparation process he provided almost allowed them to avoid all the pitfalls.

As for the high pressure of 10~50MP, it is not a problem at all for Yu Yuncheng and others.

Thinking of this, Gao Zhendong reminded them: "You should pay attention to two things."

"You say." Not to mention two pieces, even if it's two hundred pieces, just give the order.

"First, pyrolytic graphite and highly oriented pyrolytic graphite are two different things, and magnetic field and annealing are two different things. You can complete them step by step. To some extent, pyrolytic graphite without magnetic field treatment and annealing can also be used first for the earliest applications."

Gao Zhendong was afraid that they would be obsessed with the best parameters and affect the work on the other side, which now had good propellants but could not get the best application for the time being.

"Yes, yes, yes. I understand. No matter whether the process is complete or not, as long as the preparation results can meet the working parameter requirements over there, we will provide them first. Improvement will be a subsequent matter." Yu Yuncheng and Lao Duan are not stupid. In the engineering application of this kind of material, "enough is good" is more appropriate than "striving for perfection".

"Secondly, after the final highly oriented pyrolytic graphite is produced, please send some to me as soon as possible. I will need it." Gao Zhendong is really useful. If he doesn't have it, it doesn't matter. Since it has been made, it would be nice to take advantage of the foreigners.

"Okay, as soon as we make the real highly oriented pyrolytic graphite, we will send you a batch of samples immediately and we will arrange air transportation!" Old Duan agreed readily. Although he also knew that Gao Zhendong could get this thing without going through them, Gao Zhendong's statement showed that he was very close to them.

Gao Zhendong was happy: "Okay, then I'll wait for your good news."

(End of this chapter)