Nanodiamond particles with their extremely high surface energy are powerful structure-forming agents that may have impact on crystallization processes in structure refinement. The diffusion of carbon additives in the formation of structural-phase state of the modified material increases hard strengthening phase content (carbides, solid solution of carbon in the metal). Contained in the batch mixture graphite-like particles shells in the process of structure formation contribute to increase of components with layer-like structure in modified composite. The nano-sized solid particles of diamond additives enable dispersion strengthening of the composite material.
NANOSTRUCTURED ANTIFRICTION MATERIALS
a) Lubricants
New principles of modification of grease lubricants with nanosized additives by forming a binary phase comprising salts of high molecular weight acids and additives nanoparticles are proposed. In this case, the nanoparticles act as reaction structure formation centers of disperse phase and functional fillers. The physical principle of modification involves injection of the nanoparticles into dispersion medium at some stage of the process of obtaining grease lubricants. Chemical principle of modification involves synthesis of nanoparticles in the process of obtaining grease lubricants from dispersion medium components.
An example of the physical principle:
Plastic complex lithium lubricant OIMOL KL EPR 2 with nano- and micro-sized additives, inputed at certain stages of the formation of the dispersed phase has a space frame made of cross-linked short-fibred filaments having a greater oil-retaining capacity, which determines its higher load capacity (in 1,60–3.3 times), expanded operating temperature range at 30-40os and increased lubrication life in 1,4-1,7 times. Field of application – recommended for the lubrication of friction units, operating under heavy loads and vibrations (mining machinery, railway transport, construction machinery, agricultural machinery), at high temperatures (press-forging equipment, heating stoves air fans, ventilation systems, etc.).
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An example of a chemical modification principle: Plastic complex calcium sulfonate lubricant OIMOL KSC WR 2 is obtained by the scheme of synthesis of nanocalcspar particles with centers of crystallization of the dispersed phase. The structure of the dispersed phase of the lubricant is a combination of star-shaped micelles consisting of thin needle-like crystals of calcium sulfonate coated with stabilizing polymer layer and connected to each other by intermolecular mutual reactions. This form of the movable frame of the dispersed phase causes high adaptability of grease to the level of mechanical and thermal loading of the friction unit. The lubrication is characterized by high anti-seize properties, water resistance, thermal stability, the unique mechanical stability, improved anti-oxidant and anti-corrosion characteristics. Sphere of application – lubrication of highly loaded sliding and rolling bearings of machinery and equipment operating at low/medium speeds at high temperatures (steel-rolling and heat power equipment, mining and concentrating machinery, road construction and agricultural equipment, railway transport, equipment glass, cement and pulp and paper industries, etc.), lubrication of mechanisms working in conditions of high (100%) humidity (maritime transport, port machinery, etc.)
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b) Electrochemical chromium-diamond coatings of the elements of friction units
During the formation of the composite coating, simultaneously with adsorbing, on the substrate layer of a lightweight film of chromium crystalline particles is deposition of dispersed phase nanoparticles (nano-diamonds), which are additional crystallization centers from electrolyte. Increase in the number of embryos leads to refill-deposition of the substrate surface layer with composite coating consisting of smaller mikrospherolites (6-10 microns) containing subgrains (200-250 nm). Modified with nanodiamond particles chromium coating is characterized by high density, hardness and wear resistance.
Sphere of application– friction units of technological equipment and machines for different purposes (hydraulic cylindersof machines, agricultural machinery, mobile machines, submersible pumps, etc.)
- PRODUCTION OF SUPERHARD COMPOSITE MATERIALS BASED ON CUBIC BORON NITRIDE AND DIAMOND NANO-, SUBMICRO- AND MICROPOWDERS FOR CUTTING AND ABRASIVE TOOLS
The use of ultradisperse powders of cubic boron and diamond nitride reduces the level of temperature and pressure of synthesis and sintering of superhard composite materials, provides composite grain structure formation, increases the density, hardness and fracture strength. Nanostructured composites on the basis of cubic boron and diamond nitride are used as highly effective blade cutting elements tools for machining of hardened steels and cast irons, and also in the manufacture of abrasive tools for superfinishing parts cutting.
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- DEVELOPMENT OF METHODS OF PRODUCTION OF CUTTING AND TRUING TOOLS (INCLUDING DIAMOND-CONTAINING) USING ELECTRIC-CONTACT HEATING
Use of electric-contact heating for sintering of powders, including diamond-containing powders, composite materials provides highly dispersed structure in the sintered high-density composite, exclusion of diamond graphitisation during sintering, the possibility of sintering process without protective atmosphere, resulting in high physical-mechanical and tribological properties of the sintered composite materials and increased operational reliability of the cutting and dressing tools based on them (diamond pencils for editing of abrasive circles, diamond ring drill for processing of non-metallic materials, carbide die for editing rebar, etc.)
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