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Vladislav Zhdanov - “The use of diamonds in high technologies is the main and key target of the diamond synthesis technologies”

15 november 2021

vladislav_zhdanov_xx.pngVladislav Zhdanov, Professor at the Higher School of Economics, Advisor to Director General - Chairman of the Management Board of the Russian Railways company, and former Vice President of ALROSA (2015-2018). He is a physicist by background. He graduated from the Ural State University (General and Molecular Physics), Diplomatic Academy of the Ministry of Foreign Affairs, City University London, Oxford University, and the Russian Presidential Academy of National Economy and Public Administration (RANEPA).

He is a prizewinner of the national competition Leaders of Russia 2020 and the author of a number of scholarly articles on the use of diamonds in high technologies. Vladislav Zhdanov told R&P about the use of synthetic and natural diamonds in modern high technologies, about the trends and prospects of their use in this area.

You received an all-round education. Why are you so interested in diamonds?

Remember Vysotsky’s words “...that means you read the right books in childhood”, I have a wonderful uncle, Anatoly Zhdanov who gave me two books about diamonds in my early childhood - “Cecil Rhodes and His Time” by Apollon Davidson and “The Diamond Hunters” by Georgy Sviridov. I read these books many times, I can say I was prepossessed with the diamond rush from the age of ten - Kimberly, De Beers, Zarnitsa, these new words fascinated me.

But this was the theoretical part, the practical acquaintance with diamonds took place at the metallurgical laboratory where my uncle Anatoly managed to synthesize diamonds by mixing graphite with iron-based powders and heating the mixture under pressure; really, the diamonds were finely dispersed and made no impression on his laboratory lady-assistants (which upset my charismatic uncle) and my classmates (unfortunately) - but to my mind, it was magic! So, my journey to the diamond world began at my uncle’s laboratory where I spent part of my childhood. I can say with a certain amount of self-irony that I have been in diamond synthesis since I was 13 years old.

Actually, my further education and great interest in diamond mining and synthesis were only inspired by the books I read in my childhood and the experiments at the metallurgical laboratory. Working at ALROSA from 2015 to 2018, I was lucky enough to get to know the issues of diamond mining better, as well as communicate with many outstanding physicists, whose experiments with diamonds are amazing; Vladimir Blank, Sergey Vartapetov, Anatoly Vikharev, Alexander Kolyadin, Victor Ralchenko, Roman Khmelnitsky are among them! The uniqueness of the work of their teams is difficult to overestimate, from academic and practical points of view! Perhaps, today, Russia has one of the most powerful schools of diamond synthesis in the world, and undoubtedly, this is the merit of the above-mentioned researchers as well. The Russian scientists and synthesis practitioners are constantly improving technological processes, equipment, and synthesis modes to achieve the most effective processes that allow achieving controlled and regularly repeatable results, which is critical for the use of synthetic diamonds in high-tech industries.

The synthetic diamond manufacturers in the West position synthetics as a technological novelty with the prefix “eco” and “conflict-free”. Does it have any bearing on reality?

The diamond synthesis is hardly a novelty. These technologies are almost 80 years old. And putting the marketing context of the prefixes “eco-friendly” and “green technology” aside, indeed, it is interesting to compare what kind of diamond production - synthesis or natural mining - is more in line with the concepts of “green technologies”. As it turned out, the question is very difficult and controversial. In part, the answer to this question is our recent work with our Skoltech colleagues described in the article “A Comparative Analysis of Energy and Water Consumption of Mined versus Synthetic Diamonds” published at the end of October in the Swiss magazine Energies (https://www.mdpi.com/1996-1073/14/21/7062/htm). We have analyzed the ALROSA’s and De Beers’ reports for recent years; thankfully, both of these companies are extremely transparent. As a result, we received the data that the average energy consumption for the production of one carat of diamonds in these companies is in the range of 96-150 kWh, and De Beers has shown a steady increase in energy efficiency in recent years. Actually, taking into account the dynamics of the increasing production efficiency, the specific energy consumption per unit of production (in our case, a carat) is one of the key parameters in the technological and sectoral sense, and in the ecological sense as well.

Also, as a result of the study, water consumption was analyzed (ALROSA’s data). In 2018, ALROSA used only 77 liters of water to produce 1 carat of diamonds; although back in 2014, according to official reports, this figure was several times higher, that is, the positive dynamics is obvious. It is necessary to clarify that most of the power used by ALROSA is produced by its own hydroelectric power plants. In addition, water goes through technological treatment cycles and is recycled using a closed loop, which also significantly reduces water consumption and increases efficiency.

Thus, we see that the environmental agenda is very important for the two leaders of the diamond industry, technologies are constantly being improved and demonstrate positive dynamics.

When it comes to synthesis, our favorite method is the High-Pressure-High-Temperature (HPHT) one! According to our data and other researchers’ data (for example, Ali, S.H., 2016), the specific energy consumption of modern presses is only a few tens of kWh per carat. It is worthy of note that these indicators relate to open-loop cooling systems. I believe that they are the most rational and effective ones. If you take a look at the HPHT presses with a closed-loop cooling system, in this case, the specific energy consumption has to be approximately doubled (the law of energy conservation is still valid) and an additional chiller would be required to remove heat from the 3-kWt cell of the HPHT press. In this case, the energy efficiency of a particular HPHT project would decrease, approaching the level of the electricity consumption required in mining the natural diamonds. The obvious environmental advantage of the HPHT method is zero water consumption for diamond synthesis!

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CVD reactor (left, foreground) and HPHT press (right) / © From the author's archive of Vladislav Zhdanov

The second common synthesis method is CVD. Some researchers show the effective figures of the specific energy consumption at the level of 77 kWh and 143 kWh per carat, but at the same time, our own results obtained in the study are modest and equal to 215 kWh. In the article “A Comparative Analysis of Energy and Water Consumption of Mined versus Synthetic Diamonds”, we also took into account and described the frequency and power of the magnetron, the performance of the reactor based on it, and we wrote a lot about the role of nitrogen, the “steroid” of the synthesis, - in general, there were many caveats. The CVD technologies are very sensitive to various factors, depend on many variables (peculiarities of the synthesis modes, reactor configuration, quality of substrates, plasma distribution, gas mixture composition, etc.). Of course, a lot depends on the expertise and skills of a technologist able to adjust the optimal production process and synthesis mode.

In other words, we see a range of CVD-specific energy consumption to be 77-215 kWh per carat, it covers the previously mentioned range of energy consumption, 96-150 kWh, in diamond mining. Therefore, I will not venture to say that any CVD diamond is a priori more “environmentally friendly” (in the sense of less energy consumption compared to a natural one). As for water consumption, really, the CVD synthesis practically does not require water compared to mining; according to our observations, it requires no more than 2 liters per carat, since water is needed only for the hydrogen plants that are the basis of the gas mixture in the CVD synthesis.

As a summary, I would like to note that not all synthetic diamonds are superior to natural ones in terms of the energy efficiency of their production. But all synthetic diamonds are superior to natural ones in terms of water consumption. Does this mean that all synthetic diamonds are “greener” than natural ones? I think, not all of them are.

What is your attitude to synthetic jewelry?

I confess that I am indifferent to the diamond jewelry market - I can’t help myself, I understand that this is the driver of the diamond industry, but unfortunately, I have no passion for jewelry projects. I believe that the gem-quality synthetics jewelry market is growing, as is the number and quality of the lab-diamond producers; the prospects for this business are obvious, given a relatively low entry threshold. The cost of the modern HPHT presses is quite “affordable”, and their payback is fast enough if you have a good technologist. The same situation is with the CVD systems, as despite their lower specific energy efficiency, the cost of the equipment has not been high-sky for a long time. At the same time, the expenditures for energy in synthesis is not the main one, therefore the CVD expansion will increase. It is no coincidence that Element Six in its promo videos shows exactly the CVD synthesis of its new Lightbox jewelry line and I also believe that the potential for the CVD synthesis is really huge.

I’ll try to explain why CVD is changing the whole paradigm of diamond synthesis. Firstly, we can cover a large area with plasma, which would allow many crystals to grow simultaneously. And theoretically, with a lot of caveats, the coverage area can be even larger - hence, it results in a qualitative leap in the performance of CVD reactors. Secondly, in 2014, the German scientist Matthias Schreck et al. published the results of the synthesis of a 92-mm (!!!) 155-carat diamond plate grown in the CVD reactor, which is extremely eloquent evidence of the CVD technology’s uniqueness. Taking into account the above, it is obvious that the size of CVD diamonds will increase, thereby increasing the demand for them in the technology and jewelry industries, where their cost depends almost exponentially on the size. Imagine diamond lenses in glasses - given its higher refractive index than that of silicon dioxide (glass), the focal length will be shorter, glasses, as a quasi-jewelry piece, will be at least elegant and more functional as the diamond’s spectrum bandwidth is unique. Thus, the jewelry market can change and new niches will appear as the synthesis technologies are developing very fast.

However, in my opinion, the use of diamonds in high technologies is the main and key target of diamond synthesis technologies. The jewelry industry is “adaptive” as ​​the exact repeatability of the product’s characteristics and parameters is not important in it and just the size and color are enough; even defects (cracks and inclusions) are the signs that make a synthetic diamond more visually similar to a natural one. For this reason, everything that “is not suitable” for high technologies may well be used in the jewelry sector where crystal lattice defects can be considered as the uniqueness of a particular stone.

What do you think about using lab-grown diamonds in high-tech sectors? Do they have a competitive advantage over traditionally mined diamonds?

I have already partially answered this question, and I will add that the crystal lattice of natural diamonds does not repeat itself, which, on the one hand, demonstrates the uniqueness of natural diamonds, but on the other hand, makes it impossible to use them in high-tech sectors where stable repeatability of parameters is required. For this reason, natural diamonds are suitable for technical use only as abrasives, but this is not a high-tech sector at all.

As for synthetic diamonds, only synthesis makes it possible to obtain a pure crystal lattice with preset properties. By changing the synthesis parameters, it is possible to obtain not only a colorless crystal, a flawless one, from the point of view of a jeweler, but also a unique crystal, from the point of view of a quantum physicist, with an NV center; and if it is not just nitrogen, but a nitrogen-15 isotope, this would be great!

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CVD synthesis scheme: The dissipation of methane (CH4) into methyl (-CH3) and atomic hydrogen (H); the capture of a methyl group by the diamond cell, and the subsequent dehydrogenization.

I sincerely believe that diamond synthesis is open for non-jewelry applications and is continuously improving. The diamond synthesis is gradually reaching the stable and high-quality parameters and characteristics, and most importantly, stably reproducible (repeatable) ones, so the commercial application of synthetic diamonds in various high technologies becomes possible. In my opinion, such applications are much more promising than just cutting and polishing a crystal and using it as a substitute for a natural diamond in jewelry pieces. I am sure that in the near future, the advanced technologies and synthesis processes will allow the lab-diamond producers to reach a qualitatively new level to achieve all the product parameters required for their use in high technologies.

What are the trends in the use of synthetics and natural diamonds in high technology? Which ones are the most promising?

Diamonds have excellent characteristics, which allows them to be used in a very wide range of applications! Today, more than 70% of synthetic diamonds are used in tools used in construction, oil and gas production, and mining where the abrasive properties of diamonds and their wear resistance are important (diamonds break into small pieces during their use, but due to the peculiarity of their crystal lattice, they remain sharp throughout the entire service life). Slightly more than 13% of synthetic diamonds are used in electronics and optics for the production of semiconductors, sensors, dosimeters, laser, and fiber optic systems, etc. where the optical and thermal characteristics of diamonds are important. About 6% are used in medicine in the diamond scalpels, laser, and radiation therapy sensors. The rest of the volume falls on diamond electrodes for water ozonation systems, diamond glass, and other narrow-focused applications for various industries.

Well-known facts about a diamond are as follows:

a) it is super hard (abrasives);
b) it has a high refractive index (optics, including X-ray);
c) it has the highest thermal conductivity coefficient (electronics, thermonuclear power engineering, etc.);
d) it is able to stably hold nitrogen and other atoms within its lattice (quantum technologies);
e) it has a high coefficient of secondary electron emission (optics, electronics);
f) it makes auto electronic (field) emission (optics, electronics);
g) it is the basis for the synthesis of new crystal structures that do not exist in nature (meta-materials).

The list can be continued, but I will talk in detail about the points on which my colleagues from Skoltech and I are mainly working now and that are mentioned in “e” and “g”.

Last year, The Journal of Physical Chemistry Letters, the USA, published two interesting articles with my co-authorship: the first is “Exotic Two-Dimensional Structure: The First Case of Hexagonal NaCl” and the second one is “Role of Nitrogen and Oxygen in Capacitance Formation of Carbon Nanowalls”. They are extremely interesting from the academic point of view since the hexagonal structure of table salt (NaCl) was obtained for the first time on the diamond lattice as a result of experiments, and the role of oxygen and nitrogen in the synthesis of new carbon structures was analyzed.

For example, now our research group is conducting a series of experiments on the deposition of gold on a diamond substrate, which allows us to make various experiments to change the electrical conductivity of this metal used in jewelry production. In addition, Vladimir Blank’s team has laid the very interesting scientific groundwork related to the secondary electron emission of diamonds, and my colleagues and I do our best to develop this direction, “burning” tunnels of different configurations in the diamond substrates in an attempt to find the optimal one.

Actually, the article about the energy efficiency of diamond production is beyond our current academic “channel”. I was lucky to meet talented scientists, colleagues, and like-minded people in this field. For us, the synthesis is just a stage in a large process of innovative application of the technologies based on diamonds or using them. Today, the synthesis, first of all, allows us to obtain high-quality diamond substrates, on which we deposit other materials or “burn” electronic tunnels in them without regret. We are researchers, not businessmen.

I would also like to mention one of the most relevant and debated “diamond” topics in the academic community - diamond quantum bits or qubits. These are truly revolutionary and have the future as the diamond qubits are finding their application in quantum technologies, and the development of quantum technologies is now a strategic goal for many research teams and corporations in the USA, EU, China, and, of course, Russia. I closely follow the publications by Fyodor Zhelezko, one of the leading physicists of our time, whose work in the field of NV centers in diamonds is aimed at improving biomedical technologies, among other things, and the possible use of diamonds is steadily increasing, this trend is obvious.

My research group has several more draft articles about diamond mining and synthesis. During the study, we compared the unit labor costs and CapEx for diamond mining and synthesis. The results will be useful to anyone who thinks about diamond production. It is these expenditure items that determine the economic efficiency of any “diamond” project; it is these figures that will help rationally plan the synthetic diamond production.

As a benchmark for diamond mining, the data were taken from two African mines - Orapa, Jwaneng, and one North American Gahcho Kue - all these mines are part of the De Beers group of companies. By the way, I would like to mention the perfectly structured reporting of the company. The transparency and orderliness of the data provided allow us to use their figures in a wide range of analytical studies and researches - we could not help using them. We again compared the methods of synthesis - HPHT and CVD - and saw that the results differ as expected, so, looking ahead, I would like to tell that again, the “old school’s” HPHT “outstrips” the CVD method in formal terms. I promise, as soon as the articles are accepted for publication, I will be ready to give a detailed report on the research to your reputable media outlet. I will only say that it is definitely impossible to “abandon” diamond mining, this diamond production technology is not going to give up in terms of economic or technological indicators; so, the story of De Beers and ALROSA continues.

In conclusion, I can’t help sharing my feeling that the books I read in my childhood “Cecile Rhodes and His Time” and “The Diamond Hunters” and mentioned at the beginning of the interview require the continuation as this is a fascinating world of high technologies and charismatic leaders, and of course, an “A Diamond Is Forever” slogan! I completely agree with this De Beers slogan and although I understand it from the point of view of quantum physics, nevertheless, its meaning does not change, there will always be demand for diamonds!

Galina Semyonova for Rough&Polished