Ultrasound elasticity of diamond at gigapascal pressures

Diamond is the hardest known material in nature and features a wide spectrum of industrial and scientific applications. The key to diamond's outstanding properties is its elasticity, which is associated with its exceptional hardness, shear strength, and incompressibility. Despite many theoretical works, direct measurements of elastic properties are limited to only ∼1.4 kilobar (kb) pressure. Here, we report ultrasonic interferometry measurements of elasticity of void-free diamond powder in a multianvil press from 1 atmosphere up to 12.1 gigapascal (GPa). We obtained high-accuracy bulk modulus of diamond as K0 = 439.2(9) GPa, K0′ = 3.6(1), and shear modulus as G0 = 533(3) GPa, G0′ = 2.3(3), which are consistent with our first-principles simulation. In contrast to the previous experiment of isothermal equation of state, the K0′ obtained in this work is evidently greater, indicating that the diamond is not fully described by the “n-m” Mie–Grüneisen model. The structural and elastic properties measured in this work may provide a robust primary pressure scale in extensive pressure ranges.

Preparation of diamond/aluminum composite with titanium coating on diamond powder by microwave technology

In this research, the diamond particles were coated with titanium by microwave heating method, then the Ti-coated diamond particles were used as raw material to fabricate the diamond/Al composites by microwave sintering. The result shows that the diamond particles could be covered with a uniform and continuous Ti coating under microwave irradiation, and the best Ti coating was obtained at 810 °C for 1 h. The metallic bond between diamond and Ti was formed to generate the intermediate transition layer of TiC. The diamond/Al composites which used Ti-coated diamond particles as raw material and were fabricated by microwave sintering show high relative density and hardness. The relative density and hardness of the diamond/Al composites increased with the temperature. While the composites were sintered at 710 °C for 1 h, the density could reach 2.855 g·cm−3, and relative density was 92.09%, which shows better microstructures and properties. There is Al3Ti alloy phase in Ti-coated diamond/Al composites, so the Ti-coated diamond can be well combined with the Al matrix, which can further improve the properties of the composites.

Team durability test of a 1.3 MW locomotive diesel engine with prototype piston rings

Objective of this work was to realize a test of durability of railway engine EMD645 with power about 1300 kW. Within the framework of this test were investigated a prototyped piston’s rings with diamond embankment. Piston rings are made of chromium layer with including of diamond powders technology with a porous chromium coating, where in pores is deposited on said diamond powder with a grain size about 1 micron. The work will be carried out of an analysis of collaboration piston – piston rings – cylinder unit in internal combustion engine and an analysis of the use of hard materials (diamond powder) in friction pairs. During work of this unit we can observe wear of piston rings, precisely - of coating which is deposited on ring to prolong service life. After testing of the locomotive engine EMD645 on the basis of the collected results are developed conclusions of the wearing intensity on piston ring and relating them to the requirements for coatings. The work aims to show the possibilities and benefits of the application of new protective coatings on structural elements of the internal combustion engine in order to reduce their wearing, which is consistent with the observed trend of technology development.

FINISH MACHINING OF THE CUTTING INSERTS FROM CUBIC BORINE NITRIDE BL GROUP COMPOSITE

Finishing methods of machining of superhard composite’s working elements based on cubic boron nitride BL group are considered. The results of the microgeometry formation research of the cutting inserts’ surfaces during machining by free powders of synthetic diamond, grinding wheels and a method of vibro-magnetic-abrasive machining (VMAM) are presented. It is shown that during VMAM the friction between the inserts’ surfaces and the abrasive particles result in microremoval of the material, which reduces the roughness of the cutting inserts’ surfaces. It is established that additional fine grinding with 14/10 mkm synthetic diamond powder provides the absence of microgeometry defects of the cutting inserts’ surfaces left by pre-machining. The result of high-quality rounding of cutting edges and the formation of surfaces of cutting inserts with less roughness is an increase in strength and wear resistance of metal-cutting tools in high-speed machining under conditions of significant loads.

Rheology effect and enhanced thermal conductivity of diamond/metakaolin geopolymer fabricated by direct ink writing

Purpose Traditional simulation research of geological and similar engineering models, such as landslides or other natural disaster scenarios, usually focuses on the change of stress and the state of the model before and after destruction. However, the transition of the inner change is usually invisible. To optimize and make models more intelligent, this paper aims to propose a perceptible design to detect the internal temperature change transformed by other energy versions like stress or torsion. Design/methodology/approach In this paper, micron diamond particles were embedded in 3D printed geopolymers as a potential thermal sensor material to detect the inner heat change. The authors use synthetic micron diamond powder to reinforced the anti-corrosion properties and thermal conductivity of geopolymer and apply this novel geopolymer slurry in the direct ink writing (DIW) technique. Findings As a result, the addition of micron diamond powder can greatly influence the rheology of geopolymer slurry and make the geopolymer slurry extrudable and suitable for DIW by reducing the slope of the viscosity of this inorganic colloid. The heat transfer coefficient of the micron diamond (15 Wt.%)/geopolymer was 50% higher than the pure geopolymer, which could be detected by the infrared thermal imager. Besides, the addition of diamond particles also increased the porous rates of geopolymer. Originality/value In conclusion, DIW slurry deposition of micron diamond-embedded geopolymer (MDG) composites could be used to manufacture the multi-functional geological model for thermal imaging and defect detection, which need the characteristic of lightweight, isolation, heat transfer and wave absorption.

Manufacturing Cellulose Nanofibers Using the Water Jet Method and Their Applications

Sugino Machine Ltd. manufactures and sells equipment for cutting, washing, atomization, and fibrillation of objects using water jet technology. By applying this technology, cellulose nanofibers (CNFs) have been successfully and efficiently produced. The feature of CNFs manufactured by water jet is that the crystallinity and polymerization degree do not decrease. A drying method has also been developed because CNFs are obtained in the aqueous dispersion state. Herein, we present their use as particle dispersant and reinforcing filler for natural rubber (NR) as case studies of CNF aqueous dispersion applications. When CNFs was used as a particle dispersant, good dispersion of water-repellent TiO2, diamond powder and inorganic pigment was achieved. When CNFs was used as a filler for NR, a specific reinforcing effect was realized. As an example of CNF application as dry powders, their use with a resin additive is investigated. When CNF dry powders was used as a filler for resin, a specific reinforcing effect was realized.

EFFECT OF NANODIAMONDS ON OPERATIONAL CHARACTERISTICS OF FILLED COMPOSITE MATERIALS

The paper presents the results of a study evaluating the effect of the addition of nanosized detonation diamond of the NA-SP brand on the characteristics of a filled polymer composition based on SKU PFL-100 prepolymer manufactured by Kazan Synthetic Rubber Plant JSC cured by 4,4'-methylene-bis-orthochloraniline. The scale of heterogeneity of the carbon powder was estimated. It is shown that the studied additive allows you to create a fairly dense and developed structure in a dispersion medium. The discussion of interfacial interaction at the nanodiamond – polyurethane interface is carried out, as well as the influence of the carbon nature of the filler particles. A possible chemical interaction between the functional groups of the prepolymer, hardener and particles of the studied additives is shown. The results of the experimental evaluation show that the combination of chemistry features (the presence of functional groups) and the mechanics of nanodiamond powder affects both the physical and mechanical properties of the filled polyurethane composition and its thermal stability. It was found that the introduction of up to 1% detonation diamond allows to increase the strength and stiffness of the polymer by approximately 2 times. As a result of the approximation of the experimental data, quadratic dependences of the physical and mechanical characteristics of the filled polyurethane system on the content of nanoscale diamonds in the range 0 - 1% (mass.) were obtained. The results of thermogravimetric analysis show that the introduction of 1% (mass.) detonation diamond powder can increase the temperature of destructive processes by about 20 °С. Anomalies in the dynamics of the process of dissociation of filled polyurethane are noted. It has been suggested that the introduction of detonation diamond leads to the initiation of secondary synthesis reactions with the formation of allophate and biuret groups with low temperature stability.

A systematic assessment of the diamond trap method for measuring fluid compositions in high-pressure experiments

A variety of experimental techniques have been proposed to measure the composition of aqueous fluids in high-pressure experiments. In particular, the “diamond trap method,” where the fluid is sampled in the pore space of diamond powder and analyzed by laser-ablation ICP-MS after the experiment, has become a popular tool. Here, we carried out several tests to assess the reliability of this method. (1) We prepared several capsules loaded with fluid of known composition and analyzed the fluid by laser-ablation ICP-MS, either (a) after drying the diamond trap at ambient condition; (b) after freezing and subsequent freeze-drying; and (c) after freezing and by analyzing a frozen state. Of these methods, the analysis in the frozen state (c) was most accurate, while the results from the other two methods were poorly reproducible, and the averages sometimes deviated from the expected composition by more than a factor of 2. (2) We tested the reliability of the diamond trap method by using it to measure mineral solubilities in some well-studied systems at high pressure and high temperature in piston-cylinder runs. In the systems quartz-H2O, forsterite-enstatite-H2O, and albite-H2O, the results from analyzing the diamond trap in a frozen state by laser-ablation ICP-MS generally agreed well with the expected compositions according to literature data. However, in the systems corundum-H2O and rutile-H2O, the data from the analysis of the diamond trap were poorly reproducible and appeared to indicate much higher solubilities than expected. We attribute this not to some unreliability of the analytical method, but instead to the fact that in these systems, minor temperature gradients along the capsule may induce the dissolution and re-precipitation of material during the run, which causes a contamination of the diamond trap by solid phases. (3) We carried out several tests on the reliability of the diamond trap to measure fluid compositions and trace element partition coefficients in the eclogite-fluid system at 4 GPa and 800 °C using piston-cylinder experiments. The good agreement between “forward” and “reversed” experiments—with trace elements initially either doped in the solid starting material or the fluid—as well as the independence of partition coefficients on bulk concentrations suggests that the data obtained are reliable in most cases. We also show that the rate of quenching/cooling has little effect on the analytical results, that temperature oscillations during the run can be used to enhance grain growth, and that well-equilibrated samples can be obtained in conventional piston-cylinder runs. Overall, our results suggest that the diamond trap method combined with laser-ablation ICP-MS in frozen state yields reliable results accurate within a factor of two in most cases; however, the precipitation of accessory minerals in the diamond trap during the run may severely affect the data in some systems and may lead to a gross overestimation of fluid concentrations.