Diamond-containing Materials Research Articles

Preparation of CrB2 mixtures and formation of briquettes for drill bit composites

The research described in the article concerns advanced methods of creating composite materials for drill bits used in extreme conditions of deep wells. The main attention is paid to development of multicomponent mixtures that ensure uniform distribution of powders of tungsten carbide, cobalt, chromium diboride and diamond. This is achieved through careful selection of particle size and proportions, which is critically important to ensure high strength and wear resistance of final materials. The Spark Plasma Sintering (SPS) method was chosen for the production of samples of carbide matrices and composite diamond-containing materials because of its ability to provide high density and uniformity of the material. SPS allows temperature and pressure control during sintering process, which contributes to the formation of materials with optimal physical properties. The article also discusses in detail design parameters of the diamond bit, including the choice of grain size of diamond powder and other components. These meters have been optimized to max-imize drilling efficiency and extend tool life. The diamond powders used in study were obtained from De Beers, South Africa and are characterized by high quality and uniformity. The results presented in the article can have a significant impact on future production of drilling tools, offering new approaches to choice of materials and methods of their processing, which ultimately can lead lower drilling costs and increased process safety. These innovations can also contribute to more efficient development of new fields, which is of great importance for the energy industry and the mining industry.

Increasing the durability of an impregnated diamond core bit for drilling hard rocks

Wear rates of impregnated diamond core bits made from two composite diamond-containing materials (CDM) are studied by spark plasma sintering (SPS) in the temperature range 20–1350 ºC at a pressure of 30 MPa for 3 minutes while drilling granite. The addition of chromium diboride (CrB2) micropowder in an amount equal to 2% of the composition of CDM 25Cdiam–70.5WC–4.5Co leads to a twofold decrease in the wear rate. The wear resistance of crowns made from CDM 25Cdiam–70.5WC–4.5Co and 25Cdiam–68.62WC–4.38Co‒2CrB2 is maximized at a rotary speed of 250 rpm and an axial load of 900 kg, and minimized at 750 rpm and 1250 kg. The increase in wear resistance of the 25Cdiam–68.62WC–4.38Co‒2CrB2 crown is due to the refinement of the grains of the main wolfram carbide (WC) phase and the formation of strong adhesion of the diamond grains to the carbide matrix. Keywords: impregnated diamond core bit; composite; tungsten carbide; cobalt; chromium diboride; durability; spark plasma sintering.

Experimental validation of enhanced separation of refractory diamond-containing materials

Experimental validation of enhanced separation of refractory diamond-containing materials

Physical and Mechanical Properties of WC‒Co‒CrB2 Matrices of Composite Diamond-Containing Materials Sintered by Vacuum Hot Pressing for Drilling Tool Applications

Physical and Mechanical Properties of WC‒Co‒CrB2 Matrices of Composite Diamond-Containing Materials Sintered by Vacuum Hot Pressing for Drilling Tool Applications

Physical and Mechanical Properties of Composite Diamond-Containing Materials Based on Fe‒Cu–Ni–Sn‒VN Matrices Sintered by Vacuum Hot Pressing

Physical and Mechanical Properties of Composite Diamond-Containing Materials Based on Fe‒Cu–Ni–Sn‒VN Matrices Sintered by Vacuum Hot Pressing

Microstructure of WC–Co–VN carbide catrix for drilling tools diamond-containing materials

The results of studies aimed at improving the structure and performance characteristics of carbide matrices WC-Co samples, formed by cold pressing and thereafter hot pressing, for drilling tools diamond-containing materials. It is shown that the introduction of vanadium nitride in an amount of 3% into the composition of the starting materials 94WC-6Co provides an increase in the hardness of the sample from 22.8 to 34.2 GPa, the strength limit in compression from 4800 to 5340 MPa and bending from 2200 to 2280 MPa, as well as reduction of wear intensity from 1710×10-6 to 5200×10-6 g/m. The revealed effect of the formation of a fine-grained structure of a carbide matrix WC-Co-VN with increased mechanical and operational characteristics indicates the need for their use in the development of effective tools for drilling oil and gas wells.

Technology of Production of Diamond-Abrasive Composites with Metal Matrix

The prospects of using the method of explosive pressing for solving urgent problems of creating high-performance diamond composites for instrumental purposes on binders of powders of fairly cheap materials are substantiated. Purpose of this work is to develop the technology of diamond-abrasive composites synthesis from powders mixtures of natural diamond and widespread low-cost iron-carbon alloys which combines explosive pressing and subsequent short-term high-temperature heating. The processes of varying the compositions of diamond-metal powder mixtures, the parameters of their explosive pressing and the modes of subsequent heat treatment of the resulting compacts are studied. It is shown that the use of explosion energy at the stage of powder briquetting opens up new opportunities for the production of high-performance diamond-containing materials with a matrix of iron-carbon alloy powders. This is due to the specifics of the explosive action which results in the activation of the bonding material which becomes obvious with further high-temperature heating in its intensive hardening and acceleration of diffusion processes. It is revealed that the shock waves create thermobaric conditions that allow for better preservation of the diamond component than with traditional methods of sintering. Samples of abrasive diamond composites with wear resistance corresponding to the level of wear resistance of industrial diamond dressers but with half the consumption of diamond raw materials were obtained.

СИНТЕЗ КОМПОЗИЦИОННОГО КЕРАМИЧЕСКОГО МАТЕРИАЛА И ИССЛЕДОВАНИЕ ЕГО АБРАЗИВНЫХ СВОЙСТВ

The innovative diamond-containing composite material formed by micro-arc oxidation on the surface of a sintered billet from a diamond-aluminum mixture has been developed. The method of the modification of the basic technology of a material obtaining has been proposed in order to reduce energy consumption and improve its frictional properties. The total time of material formation is reduced by replacing a part of the aluminum powder with white fused abrasive alumina powder, subsequent sintering and formation of diamond-ceramic material by micro-arc oxidation. It was found that the addition of corundum powder has a positive effect on the progress of the microarc oxidation process. A basic structural model of the new material has been developed. Friction tests have shown the advantage of diamond-containing materials of modified composition in comparison with the basic one. It is proposed to use the new material as a tool one for precision abrasive micro-processing of solid materials.

Synthesis and friction properties of a multifunctional diamond-containing ceramic material

Abstract The paper investigates the fundamentals of the technology of forming multifunctional composite diamond-containing materials with a ceramic matrix of an aluminum oxide. It shows the results of comparative tests of triboengineering properties of the obtained material. The developed technology for creating a billet for a diamond-containing composite ceramic material uses powder metallurgy (aluminum powder and dispersed diamonds). The paper determines optimal modes to form a billet. A sample of a composite mixture has been modified by microarc oxidation. It had a hardened layer of a ceramic matrix on its surface, and a dispersed diamond evenly enclosed in it. There is a description of features of the microarc oxidation technological process of a part from a sintered diamond-aluminum mixture compared with aluminum alloys. It is determined that the thickness of the formed ceramic layer is several times higher compared with the parts made of non-porous aluminum alloys. Moreover, the alkali concentration in the electrolyte and the relative density of a sintered billet have the greatest effect. There are two types of ceramic diamond-containing materials based on the proposed technology. They are: antifriction construction materials for sliding friction units and tool materials for abrasive processing. Triboengineering tests of materials with a small grain size of diamonds revealed their good antifriction properties even without lubricating with liquid materials. It has been established that an abrasive tool made from a material with a high grain size of diamonds has higher wear resistance and productivity compared with traditional abrasive materials.

Functional Approach to Development of Hybrid Technology of Cutting Diamond Carbides

Background: Modern composite materials have a number of advantages in comparison with the traditionally used ones and allow implementing new methods of processing, which makes the finished product cheaper and makes its use more efficient.Objective: In order to improving the surface quality and productivity taken by A functional approach. Method: A functional approach to the development of cutting technologies for Carbide and Super Hard Multilayered Composites is considered. It allows, by alternating the effects of different nature, to obtain qualitative edges, to lower the residual stresses in the surface layers, and to achieve a high surface quality. The essence of the approach is that the method of impact is determined on the basis of a morphological search of options for the execution of individual surface elements, each of which, combined into a set, uniquely forms the function of the finished product. The cutting is determined by a rational sequence of execution of technological transitions, provided that each harmful intermediate function at the finish stage turns into neutral or complements the required useful function.Results: Examples of figured cutting of plates from polycrystalline diamond-containing materials are given, the results of obtaining qualitative edges are shown.Conclusion: Thanks to the proposed technology based on the use of a functionally oriented approach, the functions of the tool for cutting are divided between the tool itself and the product part. As a result, the processing speed increases more than 3 times, and a high cut quality is achieved.

Functional Approach to Development of Hybrid Technology of Cutting Diamond Carbides

Background: Modern composite materials have a number of advantages in comparison with the traditionally used ones and allow implementing new methods of processing, which makes the finished product cheaper and makes its use more efficient.Objective: In order to improving the surface quality and productivity taken by A functional approach. Method: A functional approach to the development of cutting technologies for Carbide and Super Hard Multilayered Composites is considered. It allows, by alternating the effects of different nature, to obtain qualitative edges, to lower the residual stresses in the surface layers, and to achieve a high surface quality. The essence of the approach is that the method of impact is determined on the basis of a morphological search of options for the execution of individual surface elements, each of which, combined into a set, uniquely forms the function of the finished product. The cutting is determined by a rational sequence of execution of technological transitions, provided that each harmful intermediate function at the finish stage turns into neutral or complements the required useful function.Results: Examples of figured cutting of plates from polycrystalline diamond-containing materials are given, the results of obtaining qualitative edges are shown.Conclusion: Thanks to the proposed technology based on the use of a functionally oriented approach, the functions of the tool for cutting are divided between the tool itself and the product part. As a result, the processing speed increases more than 3 times, and a high cut quality is achieved.

Regularities of structure formation in diamond−Fe–Cu–Ni–Sn–CrB2 systems

We study specific features of the formation of micro- and nanostructures in diamond−Fe-Cu-Ni-Sn- CrB2 composite materials obtained by sintering in the molds placed in a muffle furnace with subsequent hot post-pressing. We also clarify the mechanisms contributing to the improvement of the mechanical properties of these composites depending on the technological modes of their production. Composite diamond-containing materials (DCM) on metallic binders, containing iron, copper, nickel, and tin, are extensively used in the production of cutting wheels, rope saws, core bits, and grinding and polishing tools with different areas of application (1). For the efficient sintering of these DCM, it is necessary to under- stand the processes running between the elements, including the interaction of diamond (carbon) particles formed in the process of graphitization of the surface with the α -Fe solid phase (2). In the present work, we develop the foundations of scientific analysis of the mechanisms promoting the improvement (or deterioration) of the structure of diamond-matrix transition zone and the mechanical properties of DCM obtained by sintering in the molds placed in a muffle furnace with subsequent hot post-pressing. It is shown that, unlike the DCM produced by using industrial technologies, the main causes of improvement of the mechanical characteristics of DCM obtained under the optimized conditions are the presence of Fe3C interlayers of nanosize thickness and the absence of graphite inclusions in the transition zone of these materials. It is also proved that the key factor for getting commercially promising DCM is the possibility of control of the diffusion of carbon (formed as a result of graphitization of the diamond surface in the stage of sintering of compositions in the furnace) into the crystal lattice of α -Fe in the course of their hot post-pressing. To improve the structure of these materials and endow them with certain specific properties, it is customary to introduce admixtures of borides, carbides, and silicides of transition metals, which can guarantee the for- mation of phases more stable than Fe3C in the transition zone (3, 4). The application of these admixtures often leads to the contamination of the transition zone with reaction products, which leads to structural instability and deteriorates the properties of DCM. The regularities of structure formation in systems with solid admixtures are not studied. This is explained by the absence of phase diagrams, mutual influence of the elements, very low concentrations of carbon formed in the course of graphitization of diamonds, and nonisothermal conditions of sintering. At the same time, the theoretical analysis of this problem is extremely complicated. However, the successful determination of the type of admixtures to the composition of the original mixture and the technolog- ical mode of sintering (P−T−t) is one of the main ways in the development of DCM with high technological characteristics. All these facts are important both for the theoretical sciences (verification of the already developed

Study of the Structural Organisation of Abrasive Composites Based on Ultrahigh-molecular-weight Polyethylene and Natural Diamond Powders

A study was made of the structural features of composite diamond-containing materials (CDMs) of abrasive designation, based on ultrahigh-molecular-weight polyethylene (UHMWPE) and natural diamond powders (NDPs), and their effect on the physicomechanical properties of the composite and the service characteristics of the tool. It was established that the composition of the composite is directly responsible for the parameters of the structure formed. It was shown that an increase in the degree of crystallinity and a reduction in the size of the supermolecular formations of the polymer binder lead to an increase in the physicomechanical and service characteristics of the material.

Investigation of tribotechnical and service characteristics of diamond-containing materials based on SHMWPE and PTFE

Investigation results of service characteristics (specific consumption of diamonds, machining capacity, glazing of tools) of diamond abrasive materials based on high-molecular polyethylene and polytetrafluoroethylene are discussed. Optimum graininess and concentration of microgrit as well as conditions of steel and mineral material machining have been evaluated for both binders. It is shown that the tools based on PTFE are advantageous for a short-time grinding of steels, while the ones based on SHMWPE are better for a long-run grinding of minerals and steels.

Molecular structural nonuniformity of ultradispersed diamond-containing material and the reasons why it arises

An analysis of IR spectra, Raman spectra, and X-ray diffraction intensity curves for diamond-containing materials obtained by the detonation method under different conditions and purified by different methods was used to examine the structural nonuniformity of diamond-containing particles and the reasons why it arises.

Evaluation of the quality of composite diamond-containing materials by their electrical and thermal conductivity

The serviceability of hot-pressed diamond-containing composite materials for application in tools depends substantially on the presence of microdefects, in particular, the residual porosity of the metal matrix, damaged diamond grains, and imperfect diamond-matrix interfaces. Experimental investigations of these defects are very difficult due to their small size and nonstandard shape as well as a strong inhomogeneity of the specimens. We propose an alternative technique of the nondestructive testing of the quality of diamond-containing composite materials, which includes measurement of the electrical resistance and thermal conductivity of a diamond-containing composite and analysis of the data obtained by the methods of composite mechanics. The quantitative estimate of quality is given in terms of two dimensionless parameters. The first of them, 0 < K < 1, reflects the quality of a sintered metal matrix, whereas the second, 0 < R < 1, is an aggregate measure of the integrity of diamond grains and the degree of perfection of the interfaces in a composite. The good agreement between theory and experiment corroborates the efficiency of this technique and the accuracy of the presented data.

Processing of wastes from manufacture of cut diamonds

Test experiments on recovery and purification of diamonds in melts based on alkali metal hydroxides and ammonium hydrofluoride were carried out. A method for processing of diamond-containing materials is suggested and apparatus for implementing this technology is described.

Thermal oxidation initiated in explosive detonation products by exothermal pyrolysis of metal acetylacetonates

Thermal interactions between solid-phase mixtures of metal acetylacetonates with ultradispersed diamond and explosive detonation products are investigated. It is shown that these processes occur through combustion. The behavior of ultradispersed diamond and carbon (not transformed into the diamond phase) during thermal oxidation initiated in air due to exothermal pyrolysis of metal acetylacetonates is examined. The combustion reactions of solid-phase mixtures of this type can find application in the synthesis of new diamond-containing materials.

Self-propagating high-temperature synthesis: a new method for the production of diamond-containing materials

Self-propagating high-temperature synthesis (SHS) is recognized as an attractive process for the production of various high-temperature and hard materials which are difficult and/or expensive to produce using conventional methods of fabrication. Using the distinctive properties of SHS, several diamond-containing ceramics were fabricated. The possibility of preservation of diamond and its properties during SHS was confirmed using the Ti-B-diamond system as an example. The addition of gas-generating additions was shown to influence the diamond grain strength. The mutual influence of the temperature and velocity of burning on the decrease in diamond grain strength is discussed. The prospects of production of functional gradient diamond-containing materials using SHS-compaction is considered. Some results of reaction sintering of intermetallic diamond-containing compositions are presented.

Rules of formation of diamond-containing materials with a metal carbide matrix at high pressures

Rules of formation of diamond-containing materials with a metal carbide matrix at high pressures