Lab diamonds "infighting"

February 14 is a sweet Valentine's Day, which also creates a hot spot for atmospheric marketing for diamonds representing love. But on this day, a very discordant voice appeared in the field of man made diamonds. A marketing article for lab diamonds known as the new "UPHT high temperature and ultra-high pressure" spread in China, which had a great impact on the industry.

So called "scientific evidence" is arbitrarily fabricated in the article, disregarding the facts and truth, and challenging the cognition of the entire industry under the banner of pseudo-popular science, but it is ridiculous that the original author cannot be verified, it is just automatic publishing and reprinting on multiple platforms. Create a marketing drama that sacrifices the industry and elevates yourself.

The core argument in the article is that the so-called "UPHT (Ultra High Temperature and High Pressure)" lab diamonds are far superior to those produced by the HPHT (high temperature and high pressure) method. The lab diamonds have more metal impurities and strong magnetic properties, so they can only be used as ordinary industrial diamonds. The synthesis diamonds produced by the UPHT method can overcome this defect and are the main rough source of jewelry-grade diamonds.

This logic is really not worth mentioning in the industry, but in recent years, with the continuous increase of marketing efforts by the behind-the-scenes marketing team, there seems to be an intensifying trend. For the vast majority of consumers who are vague about the concept of lab diamonds and new practitioners in the industry For those who are not careful, they will fall into the misunderstanding of cognition, and individual cases of being deceived will lead to innocent damage to the reputation of the entire industry. A typical mouse feces ruins a pot of porridge. In order not to let the wrong marketing concept continue to affect the market development, it is necessary to write some basic popular science for the industry to help the industry develop healthily and sustainably.

1. The appellation of "HPHT" is a globally recognized method of producing artificial diamonds, while "UPHT" is not a specific method for synthesis diamonds, but a registered trademark of a company.

The basic principle of the HPHT method for producing lab diamonds is to simulate the environment in which diamonds are formed in nature, and through external pressure conduction, a temperature difference is caused in the synthetic block, so that the graphite powder in the upper high temperature area is used as a carbon source in a high temperature and high pressure melting state, and the lower layer is low temperature. The diamond crystallization area continuously transports free carbon atoms, so that the previously buried "diamond seeds" continue to grow, and finally reach specifications that can be used as jewelry.

The HPHT method is a common name used by the industry to produce diamonds using the above principles. It is also called the static pressure method. It is also subdivided into: BELT and BARS. "UPHT" is just an artificial addition of an Ultra on the basis of HPHT. , Recognized and used by international industry-related authoritative organizations and organizations. To put it bluntly, it is a word game of marketing with Chinese characteristics. Adding a tall name will create a new concept and catch the market's attention. If the marketing is successful, it is not difficult to imagine. In the future, it is estimated that SPHT (Super), EPHT (Extream) and other derived concepts will be available, which will cause the market to become chaotic;

2. The HPHT method without metal catalyst does not exist at present

To know that the HPHT method to produce lab diamonds, the core is to re-arrange the carbon atoms, and only the graphite in the molten state can provide the rearranged single carbon atoms. At present, the domestic production of HPHT diamonds mainly relies on six-sided top equipment, and the six-direction top hammer is to transmit pressure to the core synthetic block and directly contact the components. The top hammer is made of tungsten steel alloy, which has enough hardness, toughness and high temperature resistance to work continuously under huge pressure and high temperature. 

However, if you do not rely on metal catalysts, under normal pressure alone, a high temperature of more than 3800 ℃ is required to melt graphite. Moreover, theoretically speaking, the higher the pressure of the same substance, the higher the melting point and boiling point, and the required temperature after pressurization exceeds 4000 ℃. Even if tungsten steel alloy has excellent high temperature resistance among many materials, it can only withstand about 2800-3500 ℃, so if no metal catalyst is added, the top hammer has melted before the graphite is melted, and naturally it cannot be synthesized. The block continues to apply pressure.

The addition of metal catalysts can not only effectively reduce the temperature and pressure during synthesis, but also increase the atomic activity, mainly by dissolving graphite with molten metal to form a similar single-atom solution. And without the help of a catalyst, it is impossible to dissociate the carbon atoms of graphite by temperature and pressure alone. The so-called "UPHT" has no metal impurities and is used as the main source of jewelry and diamonds. Naturally, it is nonsense. The low-level marketing methods that depreciate the HPHT recognized by everyone and elevate the "UPHT" created by themselves violate the basic scientific principles. , and a little deeper research will reveal the clues.

Another fact is: the diamond rough produced by the top domestic HPHT technology has greatly improved its clarity, which has solved the problem of mixing metal catalysts, and can even reach a flawless level. Without any abnormal performance, it may be the so-called "UPHT" of marketing.

Similar to this is the CVD (chemical vapor deposition) method. At present, the main method used for lab diamonds is one called microwave plasma (MPCVD), and then an enhanced microwave plasma (PECVD) is created to fabricate PECVD far. Better than MPCVD, PECVD is still a registered trademark, not a common name in the industry.