Thermal spraying is a material processing process that works by covering a substrate with a coating to change the properties of a certain aspect of the substrate. Different materials can achieve different effects, such as titanium nitride coating can improve the wear resistance of the material, and zirconia coating can play a role in high temperature resistance in addition to wear resistance.

As a materials scientist, Qin Hai has some understanding of the properties of various materials, and as soon as Leng Yuming said that the material to be coated by the customer is ferrite, he knows who the other party is, because at least in that era, the most important role of ferrite material as a material coating is to absorb radar waves, and the only one who needs this function is the military.

The use of ferrite coatings to achieve the stealth effect of aircraft and other equipment was a very common practice in those days. Although it belongs to the military secrets of various countries, some clues can also be seen from some documents. China's scientific researchers in the field of military industry learned this technology from some foreign literature, and began to practice it, and Qin Hai, as a traverser, knows the development of this technology, as well as its various defects.

Ferrites are various types of compounds formed by the oxidation of iron. The chemical formula of spinel ferrite includes a divalent metal ion, such as divalent manganese, cobalt, nickel, copper, etc.; Two trivalent metal ions, generally trivalent iron ions; and four oxygen ions.

The use of spinel ferrite as a absorbing material is relatively simple and the price is relatively low, but its disadvantage is that the density is too large and the absorbing frequency band is too narrow. If you want to increase the frequency width of the absorption, you need to use multiple coatings, each for a frequency band, which makes the coating too thick. will increase the weight of the equipment.

For example, the specific gravity of a ferrite material is about 5, and if the coating thickness is 4 mm and the coating area is 50 square meters, then the weight of the entire coating can reach 1 ton, which is for a stealth aircraft. Undoubtedly an unbearable additional burden.

Qin Hai did not specialize in the study of stealth materials in his previous life, but he participated in some peripheral consulting work, and he still had some understanding of some major technical direction issues. He knew that focusing his research on ferrite materials would be a detour, so he couldn't help but remind himself of his peers.

Li Zhongyun and Wu Honglin are naturally not engineers from Tongjiang Mining Machinery Factory, their real identities are researchers from the 70X Institute of Military Industry, and they are conducting research on stealth materials for stealth fighters. At present, the research ideas of 70X Institute for stealth materials are still limited to the use of spinel ferrite materials. The researcher purchased three thermal spraying machines from Qingfeng Agricultural Machinery Factory to spray ferrite materials. As a result, it was found that the adhesion of the material was not enough, and I couldn't solve this problem, so I had this trip to the Blue Point factory.

According to Li Zhongyun and Wu Honglin's original idea, they just went to the Qingfeng factory to learn about the technical details, and there was no need for the technical personnel of the Qingfeng factory to really intervene in this research, after all, this was a confidential project involving the national defense and military industry, and non-governmental people could not be allowed to participate. Who would have thought that as soon as Qin Hai came up, he said conclusively that they were taking a wrong path. They also said such suggestive words as "employing people without suspicion", and they had to pay attention to it.

After the two left the Qingfeng factory. I made a phone call to the leader of the unit and told me about the situation. A researcher at the 70X Institute happened to have come to the missile base in Anhe to participate in the missile tail diagnosis work and knew Qin Haiqi's person, so as soon as the unit leader immediately instructed Li and Wu to go to the provincial military district to contact Yue Guoyang in order to have a comprehensive understanding of Qin Hai's background.

Yue Guoyang listened to the narration of the two. patted his chest at the moment and said that Qin Hai, a comrade, can be trusted, as early as a few years ago, the political department of the provincial military district had screened his political background, and his business has become bigger and bigger over the years. There is no possibility of getting involved with hostile forces outside the country. Regarding Qin Hai's assertion that ferrite spraying was a misguided way, Yue Guoyang laughed and told Li and Wu that Qin Hai's attainments in materials science were unfathomable, and if they had difficulties, it was the best way to find Qin Hai.

With a suspicious mentality, Li and Wu returned to Qingfeng Factory and asked to meet Qin Hai. In their thoughts, if Qin Hai could accurately tell where they came from, it would prove that Qin Hai did know stealth materials, and it was indeed possible to help them. If Qin Hai didn't even guess what they were doing, there would be no need to talk about the rest of the matter.

"Chairman Qin, we didn't know about your situation before, so some things were kept secret from you, you can understand this, right? You're right, we're engaged in aircraft stealth materials, so why do you think ferrite spraying is a misguided path? Isn't this what foreign aircraft and missile stealth technologies do? Wu Honglin asked.

Qin Haidao: "Because our factory is making thermal spraying equipment, I also pay a little attention to the technology in this regard. You are right, there are indeed foreign countries that use ferrite materials as aircraft stealth materials, and there is not much literature in this regard, but some clues can be glimpsed. However, as far as I know, the use of ferrite materials as stealth materials can only be regarded as the first generation of stealth technology, and the defects of ferrite materials in stealth must be clear to you. ”

"We're trying to overcome these shortcomings, and we're using the thermal spray process, which is also an experiment." Wu Honglin said.

Qin Hai nodded and said: "That's right, judging from the literature, the foreign practice is to mix epoxy resin with ferrite materials to make coatings for surface coating, and your use of thermal spraying methods can improve the strength of the coating, and reduce the use of resin, which is indeed a progress and worthy of recognition." ”

"......" Li Zhongyun and Wu Honglin were speechless, if Qin Hai's words came from the mouth of the director, they might still be a little excited, but such a young man said something "worthy of recognition" in such an old-fashioned manner in front of these two experts, it seemed to be a little weird.

Qin Hai didn't care about the relationship between the two, when it came to stealth materials, he was not as professional as these two, but in terms of understanding the future technology trends, he was enough to be the teacher of these two.

"The defects of the ferrite material itself can not be completely made up for by changing the coating process, so at present, other stealth materials are being studied abroad, according to my judgment, the future ferrite materials will be fully replaced, we are now spending too much energy on ferrite materials, and the final result can only be a beat behind forever. Since we know that other materials are more promising, why can't we use our limited human and financial resources in these areas? Qin Hai said generously.

Li Zhongyun and Wu Honglin exchanged a look of surprise, and then asked tentatively: "Chairman Qin, do you think that ferrite materials must be outdated, so what materials will be used in stealth technology in the future, do you understand?" ”

"I don't dare to say that I understand, but I just have some personal opinions, which can be regarded as throwing bricks and stones." Qin Hai said, "According to my analysis, microwave stealth materials can be divided into two categories. The first category is inorganic materials, including various metal powders, metal fibers, carbon black, carbon fibers, graphite materials, ceramic materials, ferrite materials and isotope materials.

The second category is organic polymer materials, including various conductive polymer materials, such as polyethylene block, polyaniline, polypyrrole, polythiophene, etc., as well as organometallic complexes.

In the long run, organic polymer materials are more promising, because of its better plasticity, after adding various dopants, it can achieve a large bandwidth of wave absorption, and the specific gravity is much lower than that of ferrite materials, which can effectively reduce the weight of the aircraft itself. ”

After Qin Hai said this, Li Zhongyun and Wu Honglin were dumbfounded. Qin Hai said that they had also seen some clues from some foreign documents, but they were far less clear than Qin Hai's induction. As soon as Qin Hai said it, they knew that these words were definitely not groundless, and people's understanding of stealth materials was already above the two experts.

Since Qin Hai had already planned to help the other party, he didn't bother to hide anything anymore. These big ideas are sometimes just a layer of window paper, and when you don't open it, you feel mysterious, and when you click on it, you find it. If Li and Wu want to find out where this knowledge comes from, he can point to a few public documents for them to peruse, and if they can't read what Qin Hai said, then they can only blame their lack of academic sensitivity. Sensitivity, who can say clearly?

"Chairman Qin, what you said is so good. Can you go back with us, I think our chief engineer and you will definitely have a lot of common language. Wu Honglin said excitedly.

Qin Hai was stunned for a moment and asked, "Chief Engineer Gu?" It can't be Teacher Gu Qinyuan, right? ”

"Exactly, why, Chairman Qin knows our Chief Engineer Gu?" Li Zhongyun was surprised.

"Uh-uh, I've been friends for a long time, but I haven't had a chance to meet each other." Qin Hai hurriedly covered up. This Chief Engineer Gu can also be regarded as a big man in the material industry, but because he has been in the military industry system, many achievements cannot be seen in academic journals, so his reputation in the society is not very great. Qin Hai in the previous life had dealt with him a few times, and as for this life, he had also heard of this name from Chen Heqian, so it was reasonable to say that Shen Jiao was also available.

Li Zhongyun said: "Both of us are Mr. Gu's assistants, and this time, Mr. Gu asked us to come over." Two days ago, we called back and told me about your situation, Mr. Gu was very interested in your point of view, and told us to ask you for advice. I didn't expect Chairman Qin to know stealth materials so thoroughly, so we would like to take the liberty of inviting you to meet our chief engineer, and he must have a lot of questions to discuss with you. (To be continued......)

PS: Recommend the new book "Da Ming Xiao" by artillery, it will be on the shelves in two days, everyone go to support it, and if possible, help give a first order or something.

The artillery is an old writer, the previous book "Full Tang Chun" was written very tastefully, it is a 3 million word book, students who are short of books can go and gnaw it, anyway, the orange is gnawed, I think it is juicy and delicious, rich in VC......