Chapter 473 Pyrolytic Graphite and CVD
"Dean Xiong, Engineer Duan, since you're talking about work, it just so happens that I also have an idea and would like to see if the hospital can support it."

When Gao Zhendong made a request, he was not polite at all. Sometimes, when everyone is familiar with each other to a certain extent, if you are too polite, people will think you are being distant. Besides, the Carbon Research Institute is always thinking about whether they can do something for Gao Zhendong, otherwise the favor will be heavy and the way to interact with others is to give and take.

Asking someone for help appropriately and helping them relieve some of their psychological pressure is also a way for people to get along with each other.

Sure enough, Dean Xiong and Old Duan looked very happy. Oh, it was so rare that they could help Chief Engineer Gao again.

Especially Old Duan, he was the one who benefited the most from Gao Zhendong. He always felt uneasy if he didn't do more.

"Lao Gao, you said, as long as it is within my ability, I will fully support it." Lao Duan patted his chest first.

"I want to make some ablation-resistant insulation materials. After much thought, I decided to turn to you guys."

These words made Old Duan dumbfounded, and even Dean Xiong looked surprised.

"No, no, Lao Gao, you said we need thermal conductive materials, that's fine, but thermal insulating materials? We're dealing with graphite and carbon, didn't you get it wrong?"

Everyone knows that graphite is a thermal conductive material with relatively excellent performance, so when Gao Zhendong asked them for ablation-resistant thermal insulation materials, they were completely confused and looked like "are you kidding me" on their faces.

Gao Zhendong shook his head: "No, pyrolytic graphite itself is a very good ablation-resistant thermal insulation material."

Gao Zhendong wanted this thing not on a whim, but was thinking about it before coming here.

He wanted to use high-hardness aluminum alloy plus insulation material to make the rocket engine casing. This should be better than the current 591 wrapped with glass fiber used by the Research Institute. At least under the same conditions, the weight should be much better.

It’s a pity that the performance of resin is not good now, otherwise it is not impossible to use fiberglass shell + insulation material directly.

As for thermal insulation materials, the only one Gao Zhendong can think of that has the conditions to realize it is the Carbon Research Institute.

As soon as Gao Zhendong said the words "pyrolytic graphite", Vice President Xiong and Lao Duan were stunned, and other comrades from the Carbon Research Institute also fell silent.

Yes, there is this thing!
This thing is relatively new. China started to develop it in 62, and it was not mass-produced until the 70s. So it is normal that it could not be thought of at this point in 60.

But Gao Zhendong reminded everyone present who were all working on carbon-related materials, and Vice President Xiong slapped his forehead and said, "Yes! The physical properties of pyrolytic graphite are anisotropic!"

To put it simply, pyrolytic graphite conducts heat in a certain direction. In that direction, it is a very good thermal conductive material, but in another direction, it becomes a thermal insulating material, which is amazing.

Although we know about it, we don't have pyrolytic graphite at the moment. We only started to work on this two years later, and the first one to do this in China should be the Metal Research Institute.

At this time, Duan Gong also remembered that Gao Zhendong had mentioned "pyrolytic graphite" when he first dealt with him.

"Yes, yes, Chief Engineer Gao, I remember you mentioned this a long time ago. It was done by some sedimentation method, right?"

Old Duan has a good memory. He can still remember most of what Gao Zhendong mentioned casually at that time.

"Yes, chemical vapor deposition."

Chemical vapor deposition (CVD) is a method corresponding to physical vapor deposition. It is a technology that exposes a substrate to a precursor. Under certain conditions, the precursor undergoes a chemical reaction or chemical decomposition on the surface of the substrate to obtain a deposited thin film.

Well, the principle is simple.

The CVD method is the method for preparing pyrolytic graphite.

Pyrolytic graphite is a crystallized polycrystalline carbon, and its lattice shape is consistent with graphite. Don't imagine that it is a piece of carbon particles bonded together in some way, and then it is easier to be rubbed apart. It is not the case. Polycrystalline carbon is polycrystalline carbon.

Let me give you an example that everyone is familiar with: steel is also polycrystalline. Who has ever seen steel being easily rubbed apart?

The most interesting thing about pyrolytic graphite is that, since the deposition is atomic, and the graphite lattice is a series of flat polygons rather than a three-dimensional structure, after the pyrolytic graphite is deposited, it is layered in terms of crystal structure, parallel to the surface of the substrate.

This results in this thing showing a high degree of preferential orientation and anisotropy, which means that everyone goes their own way.

Taking the heat mentioned by Gao Zhendong as an example, pyrolytic graphite is an excellent thermal insulation material in the direction perpendicular to the substrate, and in the direction parallel to the substrate, it becomes a very good thermal conductor, which can be as high as 1500W/mK. How good is this thermal conductivity? In human terms, it is 4 times that of copper and 7 times that of aluminum.

Moreover, this crystalline carbon has a zero porosity that is close to the theoretical density. That is to say, the density is calculated based on the atomic weight and crystal structure, and the density of this thing is close to the theoretical density, which is something that ordinary graphite cannot achieve.

At the same time, it is chemically pure (99.5%) crystalline carbon, and is basically free of adhesives and other impurities on a macro scale, which also brings it excellent other properties.

It has extremely high chemical stability and inertness at high temperatures and excellent mechanical properties.

The usefulness of this thing can be understood simply by saying it - it is an excellent neutron moderator, and its performance is very good under high temperature and high radiation. However, Gao Zhendong is not able to explain this now.

After listening to Gao Zhendong's review paper-like introduction, both Vice President Xiong and Lao Duan expressed great interest, especially Lao Duan, who was simply enthusiastic.

"Old Gao, is this thing really that good?" Although they vaguely knew about this material, they were certainly not as clear about its performance and characteristics as Gao Zhendong was now.

Gao Zhendong smiled and said: "The above are all theoretically derived things. There will definitely be a certain distance in practice, but it is definitely much better than the extrusion, bonding and other types of graphite we are currently working on."

Gao Zhendong took precautions. What he understood was based on the technological environment decades later. It would probably not be possible to achieve that level of technology now, but it should not be a problem to realize part of it.

As for extruded and bonded types of graphite, these are the two types of graphite that Gao Zhendong helped them solve the problem with earlier.

Vice President Xiong said, "Chief Engineer Gao, although the principle of this thing is simple, I'm afraid it's not that easy to make. Can you keep up with the progress of your main project?"

Gao Zhendong smiled and said, "It's hard to say. This is a brand new method and field. Anything can happen. There is no need to worry about this. For me, even if I don't have this thing, I have backup materials for my project, so it doesn't affect its comprehensive indicators much."

Pyrolytic graphite is a good thing, but it does not mean that it must be used. The modified Raiden-1 does not require particularly extreme equipment. To put it bluntly, even without it, Gao Zhendong and his comrades from the Institute of Missile Research can still make this bullet well by adding more flour and water.

As for Gao Zhendong's statement that CVD is a brand-new method, it is because CVD is a general term for a type of method, and the process requirements are completely different when processing different materials. Even if CVD of a certain material has been done, the guidance for CVD of new materials is still limited.

But pyrolytic graphite is very useful for other industries. Otherwise, they would not have started working on this thing in 62, and would not have developed it until the 70s. At that time, there were so many things that were urgently needed, and those that were not very important could not catch up with this train.

Vice President Xiong nodded and said, "Since you have a substitute, there is no need to rush. We need to think about this matter. It may make a lot of noise and be difficult to make. We also have a lot of urgent work to do."

This statement is both righteous and objective. If you have no other way, then we can find a way to help you, but since you have other ways, then we have to make a decision based on actual conditions and work needs.

Gao Zhendong nodded to show his understanding, saying that everyone had specific work and difficulties to face.

Old Duan was scratching his head and fidgeting, as if he felt very sorry to miss this opportunity.

Gao Zhendong looked at it and laughed. If he were in my place, he would also be itching to try. He had clearly seen the most cutting-edge technological direction in his industry, but there was a possibility that he could not implement it. Anyone would be itching to try.

To comfort Old Duan, Gao Zhendong said with a smile: "Old Duan, don't worry. The people I use for this material are not anxious, so why should you be anxious? If you are ready to make efforts in this direction, I can provide some information. All the comrades of 1761 in Haihekou are engaged in CVD technology. Although many requirements may be different, it may be of certain reference value. If you need it, you can consider going to him to communicate."

Gao Zhendong was referring to Yu Yuncheng. After returning to 1761, he thought about it, did a lot of research, comparison and consideration, and decided to follow Gao Zhendong's advice. This CVD process is indeed a very promising technology and there is a lot of room for improvement.

For 1761, Yu Yuncheng also has some of the same feelings as Gao Zhendong in the Third Rolling Mill. No matter what is done, his opinions carry more weight and he has more freedom. 1761 also strongly supports his decisions.

For Gao Zhendong now, in addition to doing it himself, integrating resources is also one of his major directions. Otherwise, he will be exhausted and will not be able to accomplish much.

This kind of thing is also one of the main work directions of many scientific research leaders.

For Gao Zhendong, the Carbon Research Institute and Institute 1761 are resources that can be integrated.

After hearing this, Duan Gong's eyes lit up and said, "Well, I have to make note of this."

After staying at the Carbon Research Institute for half a day, during dinner, he left behind the legend that Chief Engineer Gao was "proficient in his work and had an amazing drinking capacity". Then he took a car back to the guesthouse of the Dongguan Institute. As for Lao Duan, he was not seen off. As the main companion, Lao Duan collapsed.

(End of this chapter)