Diamond polycrystalline PCD
Diamond polycrystalline is a new super-hard abrasive. It is generally considered to be composed of many diamond grains or diamonds.
Since the development of diamond polycrystalline by simulating natural diamonds, according to different mechanisms, different manufacturing processes have been adopted to form a series of different forms, characteristics and functions. Artificial polycrystalline products mainly include sintered polycrystalline diamond, grown polycrystalline diamond and polycrystalline diamond with a substrate.
magnetic separation
Magnetic diamond is a non-magnetic material. In the magnetic separation process, diamonds with different magnetic properties are divided into magnetic grades, medium magnetic grades or weak magnetic grades through magnetic and mechanical forces.
Diamond sorting
First is plastic processing, then acid treatment and screening. It is rougher than 140/170, semicolon selection, magnetic separation, detection and storage, and less than 140/170. The type selection is usually made on the electromagnetic vibrator. The working principle is to use particles of the same density and different shapes. Due to the different coefficients of friction, the trajectory of the tilted vibration table is also different. And separate particles of different shapes.
Purification and separation of diamonds
After the diamond is synthesized, it needs to be immersed in a mixed concentrated acid, then the graphite is washed away, and the metal is removed with dilute acid: ball milling, spin-drying the graphite, drying, acid and alkali treatment, alkali removal of pyrophyll wax, washing and drying to separate process.
Graphite
In graphite leaching, the bond between the layers is weak. The shear stress caused by the ultra-high temperature causes the graphite particles to be broken and refined, and stacking faults occur. The result can be used as hexagonal diamond in the structure of lead-zinc deposit.
Before and after solvent contact and melting, graphite carbon atoms and their clusters enter the flux catalyst through certain defects (such as vacancies and clusters, molten holes, etc.). Within a certain melting temperature range, the flux catalyst has a short-range ordered structure. The carbon atoms and their clusters enter the fluxes in a closely ordered structure, and each flux forms an ideal interstitial solid solution.
Under high pressure, the spacing of the graphite layers is compressed. The vibration of carbon atoms will increase at high temperatures. Under the action of high temperature and high pressure, the atoms corresponding to each layer are regularly approached, and a covalent bond perpendicular to each layer is established between each layer. And regular deformation is the deformation of the graphite layer into a rhombus structure. Finally, graphite is converted to diamond.
Diamond synthesis
The main raw materials for diamond synthesis are graphite and catalyst.
There are three single substance: usually achieved by excess elements and their neighboring elements (Fe, Co, Ni, Pt, Cr, Mn, Ta).
Alloy: A binary or ternary alloy composed of the first group of elements, such as Ni-Mn, Ni-Mn-Fe, Ni-Mn-Co, Ni-Mn-Cu.
The synergistic catalyst consists of two or more elements, which alone do not act as catalysts or metal compounds (or alloys), plus one element, such as Nb-Cu, Mo-Mg, Cu-Cr, Cu-Ti and NbC- Cu. The pressure transmission medium is Yezra.
The main characteristics of diamonds
Diamond's outstanding performance.
High hardness, wear resistance, suitable for cutting, grinding, sawing and drilling tools.
The friction coefficient is small. Suitable for wire drawing dies, high-speed bearings, precision navigation, pan head protection and grinding.
With good thermal conductivity, it can be used for large-scale high-power integrated circuit substrates, solid-state microwave devices, solid-state laser fins, and ultra-thermal sensors.
The light transmittance is large at all wavelengths. It is suitable for various optical lenses and optical window protective films.
It has good chemical stability and is suitable for rectifiers, transistors and thermometers.
Good infrared transmittance, suitable for infrared remote sensing and remote measurement.
It is sensitive to ultraviolet light and is suitable for ultraviolet lasers of the cosmic communication system.
Sensitive to sound vibration, suitable for high-fidelity speaker diaphragms.
The fastest sound propagation speed.
Semiconductors ban broadband
Classification and use of diamonds
Diamonds are usually divided into natural diamonds and synthetic diamonds. The crystal shape of natural diamond can be divided into single crystal, conjoined crystal, and polycrystalline. Types of industrial classification of diamond: GB/T 23536-2009 stipulates the variety code and application range of synthetic diamond powder: RVD is used to make resin, bonded abrasive or abrasive paste; MBD is used to manufacture metal bonded abrasives, electroplating products, Drilling tools, abrasive paste; SCD is used to manufacture metal-bonded abrasives, geological drill bits and cutting tools. SMD is used for cutting tools, geological drill bits and dressing tools, and DMD is used for dressing tools and other single-grain tools.
Previous：How to sharpen concrete diamond core drill bits Next：Who invented the diamond blade?
Thank you for your interest in the above content, please leave us inquiry, you can expect a response within 24 hours.
Required fields are marked *
|
|
|
|
