image: Different phases of diamond nozzle production. view more
Credit: © NUST MISIS
Scientists from the Laboratory of Ultrahard Materials (National University of Science and Technology "MISIS") have managed to create a unique type of a synthetic diamond polycrystal. Reinforced with specific nanomodificators, it has become the basis for an innovative diamond nozzle for waterjet cutting machine, massively used in mechanical engineering, manufacturing and aerospace industry. The wear resistance of the new diamond polycrystal is 30-50% higher than in the best world analogues.
Due to its versatility, waterjet cutting technology is used all over the world in various industries - engineering, aviation and aerospace, electrical and glass, housing and industrial production, in the manufacture of art products, construction, production of promotional products.
This is a type of material cutting where a jet of water and abrasive material is used as the cutting tool instead of the cutter. Water is emitted at high speed and under high pressure. The physical essence of the mechanism is the separation and entrainment of the particles of the cut material by the high-speed flow of solid particles. In natural conditions, this process, occurring naturally, called water erosion.
One of the functional elements of the machine is the so-called jet-forming nozzle, through which a jet of water and abrasive moves at a huge speed under pressure of about 4000 atmospheres. This jet is able to cut almost any material, metal and stone, respectively, machine parts in contact with it - too. Accordingly, the extreme strength and wear resistance of the nozzle is one of the main determining parameters for the performance of the cutting machine.
Only the hardest and most durable material on Earth - the cubic form of carbon, diamond - is able to resist the water jet. Scientists from the Laboratory of Ultrahard Materials (NUST MISIS) managed to strengthen the jet-forming unit and increase the life of the unit as a whole by creating an innovative polycrystal.
"The unique diamond polycrystal synthesized in the laboratory is the result of the interaction of graphite with molten catalysts at ultrahigh temperatures and pressures, as well as nanodisperse hardening of the sample by special modifiers based on titanium nitride", - Nikolai Polushin, PhD, project leader, Head of the Laboratory of Ultrahard Materials.
The obtained polycrystal has an increased resistance to abrasive (abrasion) effects. According to the results of laboratory tests, its resistance exceeds one of analogues by 50%. "In general, the synthesis of artificial diamond is in itself a complex process, which is the effect on the original graphite for a strictly defined time of extreme temperatures and pressures", - Polushin adds.
On the basis of the synthesized material, the laboratory engineers have already produced the first batches of diamond nozzles for use in the waterjet cutting machine. Tests have shown that its use increases the service life of the unit by 1.5-3 times, and also allows to increase the pressure and flow rate in it, and therefore process even more solid and durable materials.
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