A wave of layoffs that has swept the entire Internet industry has intensified. China's Internet industry has experienced several crises and major changes in the past development process. There is also a "brief history of layoffs by major Internet companies". Hot search, JD.com has a wide range of layoffs in this round of layoffs, and all its subsidiaries are involved. Most of the layoffs are between 10% and 20%. Among them, Jingxi Guangdong and other theaters have all laid off staff. Tencent also reported the news of downsizing and layoffs. Among them, Tencent PCG (Platform User Content Business Group) laid off 30% of its staff, iQiyi laid off 12% of its staff, Kuaishou was reported to have laid off 30% of its staff, and the e-sports department of Station B laid off 90% of its staff.
Mass layoffs on the internet have created a host of socioeconomic issues, including boron nitride powder.
Cubic boron nitride (CBN) is a super-hard material synthesized by hexagonal boron nitride and catalyst at high temperature and high pressure. Among the super-hard materials which have been industrially applied, the hardness of CBN is second only to diamond. The thermal stability of cubic boron nitride is much higher than that of diamond, and it has greater chemical stability to iron series metal elements, so cubic boron nitride abrasives are widely used in the field of cutting and grinding of iron-based metal products.
Types of Cubic Boron Nitride CBN
There are two kinds of cubic boron nitride: single crystal and polycrystalline sintered body.
The single crystal is prepared by hexagonal boron nitride and catalyst at a pressure of 3000 ~ 8000 MPA and a temperature of 800℃ to 1900℃. Typical catalyst materials are selected from alkali metals, alkaline earth metals, tin, lead, antimony and their nitrides. The crystal forms of cubic boron nitride include tetrahedral truncated cone, octahedron, crooked crystal and double crystal. Industrial cubic boron nitride is available in black, amber and metal-plated surfaces, and the particle size is usually less than 1 mm.
Application of Boron Nitride Polycrystals in Metal Cutting
Cubic boron nitride polycrystal (PCBN) tool is a kind of super-hard material product which is composed of many fine grains (0.1μm 100μm) CBN.
It not only has high hardness and high wear resistance, but also has the characteristics of high toughness, chemical inertia, red hardness and so on, and can be sharpened by diamond grinding wheel. It shows excellent cutting performance in all aspects of cutting, and can achieve stable cutting at high temperature. it is especially suitable for machining all kinds of hardened steel, tool steel, chilled cast iron and other high hardness difficult-to-machining materials. The tool has the advantages of sharp cutting, good shape retention, high wear resistance, small unit wear, less correction times, and is conducive to automatic machining. it is suitable for all cutting processes from roughing to finishing.
Performance and Properties of PCBN
PCBN not only has most of the properties of CBN, but also overcomes the shortcomings of directional cleavage of CBN single crystal plane, and has many performance advantages.
1. High hardness. The hardness of PCBN tool is second only to diamond and much higher than that of cemented carbide and ceramic tools, so it can process hardened steel, cast iron and cemented carbide with hardness above HRC60.
2. High wear resistance. The wear resistance of PCBN tools is much higher than that of cemented carbide and ceramics, and its service life is usually 3 to 5 times longer than that of ceramic tools and 5 times to 15 times that of cemented carbide tools.
3. High chemical inertia. The chemical reaction between PCBN and iron group elements and their alloys is not easy to occur at 1200℃ to 1300℃, which overcomes the chemical affinity between polycrystalline diamond tools and iron, has high oxidation resistance, and the bonding and diffusion effect on various materials is much less than that of cemented carbide.
4. High thermal stability. The heat resistance of PCBN can reach 1400℃, which is much higher than that of diamond tools (700℃ to 800℃). It is proved that the cutting temperature above 1100℃ can still maintain high sharp cutting performance, which is suitable for dry cutting.
5. High thermal conductivity. Among all kinds of tool materials, the thermal conductivity of PCBN is 79.54W/(m·k), which is second only to diamond and much better than cemented carbide, and the thermal conductivity of PCBN will be improved with the increase of temperature.
6. Low friction coefficient. Compared with other tool materials, the friction coefficient of PCBN is low. The friction coefficient between PCBN and different materials is about 0.1 ~ 0.3, while that of cemented carbide is 0.4 ~ 0.6, and the friction coefficient decreases with the increase of cutting speed, so that the cutting force decreases and the phenomenon of chip sticking is reduced.
Application of Cubic Boron Nitride in Grinding Field
Cubic boron nitride grinding tools have excellent grinding performance, which can complete the processing of difficult-to-grind materials, improve productivity and effectively improve the grinding quality of workpieces. It can also strictly control the shape and size of the workpiece and improve the surface integrity of the workpiece after grinding, so as to improve the fatigue strength of the parts and prolong the service life.
Cubic boron nitride micro-powder is suitable for resin, metal, ceramic and other binder systems, can also be used in the production of polycrystalline composite sheets, can also be used as loose abrasives, grinding paste and so on.
Supplier of Boron Nitride BN Powder
Luoyang Tongrun Nano Technology Co. Ltd. (TRUNNANO) is a trusted global chemical material supplier & manufacturer with over 12-year-experience in providing super high-quality chemicals and nanomaterials including silicon powder, nitride powder, graphite powder, zinc sulfide, calcium nitride, 3D printing powder, etc.
If you are looking for high-quality BN powder, please feel free to contact us and send an inquiry. ([email protected])
Cancer cells can "stretch out a big hand" and take away the mitochondria of immune cells. The Harvard Medical School research team cultured mouse and human breast cancer cells and immune cells, such as killer T cells, and used field emission scanning electron microscopy (FESEM) to observe the relationship between cancer cells and immune cells. interactive. Interestingly, they found that cancer cells stick out long nanotubes, typically within 100-1000 nanometers in diameter, each of which connects to multiple immune cells along the way. The researchers used the drug L-778123, which inhibits the formation of nanotubes, for treatment. The higher the concentration of L-778123, the better the treatment effect.
It is used in various high-tech fields, so the market demand for boron nitride powder will continue to rise. We are a quality supplier of boron nitride powder, please feel free to contact us.
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