The abstract "Diamonds are long-lasting, and a eternal rumor". On this Tanabata, whether you have echoed this classic advertisement in your ear. The value of diamonds (diamonds) is naturally high. Whether it is commercial value or application in high-tech fields, it all explains its...
"Diamonds are long-lasting, and a eternal rumor". On this Tanabata, whether you have echoed this classic advertisement in your ear. The value of diamonds (diamonds) is naturally high. Whether it is commercial value or application in high-tech fields, it is all about the meaning behind it. In recent years, large single crystal diamonds have increasingly become the focus of the industry giants' competitive development. The purpose is naturally to increase the added value and to seize the high-end areas. Today, Xiaobian will take you to talk about why the big single crystal diamond is so valuable. Large single crystal VS gem grade
Diamond enamel diamond
The pursuit of diamonds by human beings should be said from diamonds. Many people think that diamonds are diamonds. In fact, this is not accurate. Diamond refers to diamonds that have been honed. It is easy to understand that diamonds are plain photos, and diamonds are beauty photos or makeup photos.
Suyan VS Beauty
Diamond VS diamond
Gemstones and diamonds A gemstone is a precious stone. It is a stone or mineral embedding that can be jeweled after being honed and polished. Generally, the gemstone contains diamonds, crystals, emeralds, rubies, sapphires and gold emeralds, or even amber. Pearls, corals, coals and ivory can all be included in the gemstone category.
Diamond is classified into gem grade diamond (also known as diamond grade diamond), bit grade diamond, and abrasive grade diamond according to particle size and quality. Gem diamonds can be used as diamond single crystals for crafts and decoration. This diamond single crystal needs to have a large particle size and a high quality, which is simply a large size and a high quality.
What is the difference between the big single crystal and the gem grade?
In fact, there are inextricable relationships between the two. Simply speaking, large single crystal diamonds are named from the material industry, while gem-quality diamonds are named from their commercial applications. Although the standards of the two are similar. However, there are still differences, and the latter have other requirements.
Since both have requirements for size, how large is the size of the single crystal and gem?
When buying diamonds, we usually hear carats, which is a mass (weight) unit, which stipulates that 1 carat is equal to 0.2 g or 200 mg, and carat is divided into 100 points, such as 50 points or 0.5 carats. In general, a 1-carat diamond has a length to width of about 6.5 mm and a thickness of about 1.5 mm (diamond density is about 3.5 g/cm3). The size requirements of large single crystals are not very clear. Generally, the size corresponding to one carat is enough to be called a large single crystal. Gem-quality diamond refers to a diamond single crystal with a diamond size greater than 1 mm.
However, many times, we often refer to gem-quality large single crystal diamonds. From here, the difference between large single crystals and gemstones is very vague, basically the same thing.
Why develop large single crystal diamonds?
Large single crystal diamonds are naturally high-grade goods in diamonds. What is the significance of developing such large single crystal diamonds? Mainly due to its high commercial value and high added value in the high-tech field, in simple terms, these areas can generate more revenue.
At present, synthetic high-grade large single crystal diamonds have approached or surpassed natural diamond single crystals in some aspects. Since natural diamond is relatively rare, synthetic diamond single crystals have gradually replaced natural diamonds and are widely used in industries such as industry, science and technology, national defense, and medical care. Of course, this type of diamond also has its unique use, especially as it is the best choice for single crystal diamond tool blanks.
Let's take a look at the use of single crystal diamonds of different sizes, as follows.
Precision cutting
As a cutting material, diamond mainly utilizes its superhard properties, as well as its high thermal conductivity, high wear resistance, chemical stability, low expansion ratio and low friction coefficient between it and the material to be cut. It is said that the outer casing of the smartphone is "cut" by an ultra-precision milling cutter made of CVD large single crystal diamond. The specific application is shown in the following table.
In addition to partial near-infrared, diamond has a high transmittance from X-ray to microwave, and has excellent hardness, high thermal conductivity, high chemical stability and low expansion coefficient. It is an excellent optical material.
Diamond has a wide band gap and a strong sp3 chemical bond, which can lock the carbon atoms firmly on the crystal lattice and is not easily impacted by the impact. The diamond can be made to withstand normal working conditions in strong radiation environments such as spacecraft and atomic energy reactors. Radiation device.
The main application of CVD diamond film
In addition, diamond has a high electron, hole mobility, high breakdown voltage, high thermal conductivity, and doping semiconductorization, which is a promising high temperature semiconductor material. A wide-bandgap semiconductor material typified by silicon carbide (SiC), gallium nitride (GaN), zinc oxide (ZnO), diamond, or aluminum nitride (AlN) is a third-generation semiconductor material with high luminous efficiency and high frequency. Features, important applications in light-emitting diodes, semiconductor lasers and so on. The diamond forbidden band width (5.5eV, significantly higher than other third-generation semiconductors), combining mechanical, electrical, thermal, acoustic, optical, corrosion resistance and other excellent performance, is currently the most promising semiconductor material. Despite the enormous potential of diamond semiconductors, the real fabrication of diamond semiconductors faces enormous challenges. Europe and Japan have invested heavily in the development of diamond semiconductors. Among them, the international giant element 6 has been exploring the application of diamond in high-purity semiconductor components.
Jewelry
Synthetic diamond is 100% diamond physically and chemically. Artificial large single crystal diamonds are now comparable to natural diamonds and even more perfect than natural diamonds, so that jewelry experts can't distinguish them with the naked eye or with low magnification magnifiers. In addition to the ability to synthesize yellow and colorless diamonds, it is also possible to synthesize extremely rare blue and pink diamonds in natural diamonds.
Synthetic Methods There are two main methods for synthesizing large single crystal diamonds, namely high temperature and high pressure (HPHT) and chemical vapor deposition (CVD).
The synthesis of single crystal diamond and diamond polycrystalline film by CVD method is very different. The synthesis of single crystal diamond requires the use of high quality single crystal diamond with special requirements as the substrate. This method has special requirements for the seed crystal used: The seed crystal must be a single crystal diamond of pure {100} plane; second, the seed crystal must have a certain size, in principle, how large the crystal seed can grow. This has limited its industrialization to a certain extent. At present, Element 6 basically represents the top level in the industry.
The method of synthesizing diamond large single crystal by high temperature and high pressure method (HPHT method) is actually a temperature gradient method. This method is relatively mature, but it also has certain limitations. The particle size, purity, processability, formability and physicochemical properties of HPHT diamonds are far from meeting the needs of modern industry, especially military and high-end technology. Regardless of the cost, considering the technology, the size of the HPHT diamond can be close to 10mm, but if it is to be larger, the equipment will be difficult to meet the requirements. Mainly materials, technologies and processes that can provide ultra-high pressure and temperature are still not up to standard. In addition, the process is difficult to control, the cycle is long, the reproduction rate is poor, and the cost is high. The obtained material has extremely high hardness and is extremely difficult to process into a desired shape. HPHT diamond is difficult to form a large area film or sheet, and its physical and chemical properties are difficult to adjust, thus limiting its application range.
The two methods are specifically compared as follows:
International
1, element 6
Main technology: CVD method and HPHT method 2. Sumitomo Electric Industries Co., Ltd. Main technology: HPHT method 3. Gemesis company Main technology: HPHT method 4. Apollo Diamond (Apollo Diamond Company)
The main technology: CVD method 5, D. NEA, Chatham synthetic diamond Main technology: HPHT method 6, New Age Diamonds (New Century Diamond)
The main technology: HPHT method 7, Tairus
The main technology: HPHT method
domestic
1. Henan Huanghe Cyclone Co., Ltd. Main technology: HPHT method 2, Zhongnan Diamond Co., Ltd. Main technology: HPHT method 3, Zhengzhou Huajing Diamond Co., Ltd. Main technology: HPHT method 4, Ningbo Jingzhu Industrial Technology Co., Ltd. main technology : CVD method
The main advantage of bioglass ceramic tube is that CaO and P2O5 can be introduced into the glass. Hydroxyapatite crystals can be precipitated by heat treatment. It has excellent biocompatibility and bioactivating properties, and other components in the composition can precipitate other components. Types of crystals ensure the chemical stability and machinability of materials, and are more promising than metals, alumina and Other Materials. Many clinical trials have been conducted to date, some for six years, and have yielded promising results.
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