History of synthetic diamond

Artificial diamond has been born for 68 years. During this period, people have continuously improved the process and achieved good results

 

The ancient Hindus used diamonds as the eyes of the statue and believed that diamonds could protect its wearer from danger. In ancient times, wearing diamonds was considered to add strength, invincibility and courage. A small diamond is a perfect gift for both men and women. The word diamond comes from the Greek "adamas", which means unconquerable or impregnable.

Diamond is the original stone of diamond. When a diamond reaches the gem level, it can be called a diamond. Smart jewelers use the refractivity of diamond to process and grind the diamond, making it shiny and become the diamond on girls' rings. To produce 1 carat of diamonds, 250 tons of raw ore need to be mined. And the diamond itself needs a lot of reworking to become a beautiful necklace or part of the ring.

 

 

In 1772, the chemist Lavasi and them jointly repeated the experiment, proving that even if the diamond does not contact with the air, it cannot burn even if it is heated. However, when it is in contact with air or oxygen, the diamond can burn when heated by a large condenser. The ignition point of diamond in pure oxygen is 720~800 ℃, and the ignition point in air is only 850~1000 ℃. In 1797, the chemist Smithson Tennant revealed that diamond is a simple substance of carbon. It is found that the gas produced by diamond combustion is exactly the same as that produced by charcoal combustion.

From the combustion heat, the combustion heat of graphite is 393 51 kJ/mol, while the combustion heat of diamond is 395.41 kJ/mol. Therefore, graphite is more stable than diamond at normal temperature and pressure. In 1799, the French chemist Molvo converted a diamond into graphite. Of course, under normal conditions, diamond still exists stably, and people need not worry about it becoming graphite. The experiment of turning diamond into graphite has stimulated people's reverse thinking. Can we turn graphite into diamond? Since then, people have shown great interest in how to convert graphite into diamond.

 

Movasan studied meteorites, meteorites and diamond-bearing rocks, and found that in addition to diamonds, they also contain graphite and amorphous carbon. After these studies, Movasan is convinced that diamond is formed by graphite and amorphous carbon in an iron-containing environment.

 

So he invented the following method of making diamond: heating the metal iron in the graphite crucible in the electric furnace to melt it, and saturating the molten iron with carbon. Then pour the molten iron into cold water. When the carbonaceous iron cools rapidly, the outer metal will solidify first, which will generate high pressure inside the metal. Diamond can be obtained by removing iron from solid with acid.

On February 6, 1893, Movasan reported the results of the artificial diamond experiment to the Academy of Sciences, which caused a sensation in all aspects. As the first synthetic diamond, the French named it "Regent" and collected it in the Louvre as the most valuable treasure. Then a craze of synthetic diamond shook the world.

 

However, all this is far from the actual situation. Although the experimental equipment has been improved, many new methods have been explored, and the amount of raw materials has been increased, but no satisfactory results have been obtained. Artificial diamond is not only small in size, but also dark in color. At that time, there was one of the largest and nearly colorless small crystals with a diameter of less than one millimeter.

 

 

In 1955, American general electrical scientist F. P. Bundy and Hall et al. synthesized diamond at 1650 ℃ and 95,00 atmospheric pressure. Under similar conditions, the product has been successfully repeated for many times. Through various physical and chemical tests, it is confirmed to be diamond. Subsequently, the methods of producing synthetic diamond are endless. Scientists have also explored the technology of synthetic diamond using molten metal (Ni, Cr, Mn, Fe, Co, etc.) as catalyst under 5-100kbar high pressure and 1200-2400K high temperature. At present, 10-carat diamonds can be synthesized.

Recently, scientists have been able to produce artificial diamonds from the ashes of deceased pets. They call it "LifeGem", which is a high-quality commemorative gem from your precious pet. Real diamonds can also be made from peanut butter. However, making this diamond requires extremely complex scientific equipment and can withstand high temperature and pressure, so it is completely unnecessary to rush to the supermarket to buy all peanut butter now. In the eyes of material scientists, diamond is just a crystal of relatively pure carbon, and there is not much special.