Search Results (109)

Single-crystal diamond is regarded as one of the most promising semiconductor materials for next-generation high-power electronic devices, quantum technologies, and extreme environmental applications, owing to its ultra-wide bandgap, exceptionally high carrier mobility, ultra-high breakdown electric field, and excellent thermal conductivity. However, the lateral dimensions of both natural and synthetic single-crystal diamond are limited, which severely restricts their large-scale industrial application. Mosaic growth, in which multiple small single-crystal seeds are laterally arranged and fused at the interfaces through homoepitaxial growth, offers a promising approach to overcoming the size limitation of seed crystals and producing inch-scale single-crystal wafers. This review systematically covers the entire mosaic growth process, including seed crystal preparation, geometric design, growth parameter optimization, and innovative processing methods. Particular emphasis is placed on the mechanisms of interfacial stress generation, along with characterization techniques and stress control strategies. Finally, future perspectives on the fabrication of large-size, low-stress single-crystal diamond wafers are outlined. Full article

This manuscript evaluates the electrochemical corrosion resistance of diamond-like carbon (DLC) coatings deposited via High-Power Impulse Magnetron Sputtering (HiPIMS) on AISI 52100 steel in synthetic seawater. While AISI 52100 steel is valued for its hardness, it is highly susceptible to localized and uniform corrosion in chloride-rich marine environments. In this study, samples were characterized using Raman spectroscopy to analyze sp²/sp³ bonding, and their corrosion behavior was assessed through potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) over 24 h of immersion. Results demonstrated that the DLC coatings significantly enhanced electrochemical stability, shifting corrosion potentials toward more noble values and reducing the corrosion current density from (1.81 ± 0.12) × 10⁻⁷ to (1.03 ± 0.09) × 10⁻⁹ mA·cm⁻². EIS data revealed high polarization resistance and effective barrier properties, despite a calculated total porosity of 3.06% resulting from intrinsic micro-defects. Although localized subsurface degradation and minor flaking were observed at defect sites, the HiPIMS-deposited DLC coatings effectively mitigated the corrosive impact of synthetic seawater, providing a significant contribution to the electrochemical barrier despite the persistence of electrolyte accessibility mediated by localized defects. Full article

The objective of the grinding process is to obtain a better surface finish (roughness, accuracy, etc.) or a high material removal rate of the workpiece. These grinding process response variables depend largely on both the grinding conditions and the topography of the grinding wheels formed during dressing. In this regard, the paper focuses on determining the optimal dressing conditions for grinding wheels dressed with diamond roller dressers during rough and finish grinding. A new multi-objective optimization approach for determining dressing conditions has been proposed, which leads to Pareto-optimal solutions for increasing the grinding process production rate, reducing roughness, and increasing the accuracy of ground surfaces. To demonstrate the performance of this approach, one process of dressing electrocorundum grinding wheels with novel diamond rollers made of medium- and high-strength synthetic diamonds with mixed grain sizes has been selected. Empirical models have been developed to examine the production rate of the grinding process, the roughness of the ground surfaces, and the accuracy of the machined parts. Multi-objective optimization based on a genetic algorithm has been performed by applying two methods: determining an optimal compromise area for the dressing process conditions, and the weighted utility function method. The novelty of the implementation is due to the process of identifying the precise optimal dressing parameters specifically for the investigated mixed-grit diamond rollers. The optimization results show that rough grinding requires uni-directional dressing with a diamond roller AC32 at a feed rate of 1.4 mm/min, a dressing speed ratio of 0.8, a dress-out time of 1.0 s, and a grit size ratio of 2.56, ensuring a production rate of 875 mm³/min, a surface roughness Ra up to 1.25 µm, and a cylindricity deviation up to 12.5 µm. For fine grinding, optimal counter-directional dressing parameters include a feed rate of 0.26 mm/min, a speed ratio of 0.23, a dress-out time of 5.0 s, and a grit size ratio of 2.2, which guarantee a minimum surface roughness Ra of 0.38 µm, a cylindricity deviation of 8.1 µm, and a production rate of at least 600 mm³/min. Full article

The quality of ground surfaces depends largely on the topography of the active surface of the grinding wheel, which, in turn, is determined both by the structure of the grinding wheel and by the conditions of the dressing process. This article proposes a new approach to improving the quality of ground surfaces by optimizing the dressing conditions with diamond rollers, based on the correlation between the roughness of the ground surfaces, the roughness of the cutting surface of the grinding wheel, and the parameters of the dressing process. A comprehensive theoretical–experimental study and modeling of the microgeometry of electrocorundum grinding wheels and the roughness of ground surfaces, depending on the dressing conditions with diamond dressing rolls made of medium- and high-strength synthetic diamonds with a mixed grit size, has been carried out. A complex quality indicator has been defined, determined as the ratio between the roughness of the ground surfaces and the roughness of the cutting surface of the grinding wheels, and models have been constructed for its determination, depending on the dressing conditions. By applying a genetic algorithm, optimal conditions for uni-directional and counter-directional dressing (dressing speed ratio, radial feed rate, the dress-out time and the ratio between the grit sizes of the diamond roller dresser and grinding wheel) have been determined, which ensure a minimum value of the complex quality indicator in combination with minimum roughness of the ground surfaces. Full article

This in vitro study compared the cutting efficiency of natural diamond burs (NDB) and synthetic diamond burs (SDB) on zirconia and natural teeth. Two types of diamond rotary instruments with identical specifications (TR-13, Tapered Round End) were evaluated using 100 zirconia specimens and 100 extracted molars. Each bur was tested through 10 consecutive cutting cycles under standardized conditions (200,000 rpm, 2 N force, water coolant). Cutting efficiency was evaluated based on weight loss per unit time (mg/min). Surface characterization was performed using field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). For zirconia cutting, NDB demonstrated significantly higher cutting efficiency than SDB at all cycles (p < 0.05), with 38.9% greater total material removal (115.97 ± 2.22 mg versus 83.46 ± 2.08 mg). NDB also exhibited lower wear rates (40.00% versus 49.68% reduction). For natural tooth cutting, no significant differences were observed between NDB and SDB (p > 0.05). EDS analysis showed that SDB exhibited greater carbon loss (13.46% versus 2.49%) and increased surface heterogeneity after repeated use. These findings indicate that natural diamond burs are superior for cutting high-hardness materials such as zirconia, while both bur types perform equivalently on natural teeth. Full article

The wear resistance of diamond dressing rolls depends on the manufacturing technology used and the characteristics of the working diamond layer, such as the type and grain size of the diamond grains, the type of bond, and the concentration and distribution of the diamonds. To optimise the lifetime of diamond rolls made of synthetic diamonds using the electroplating method, this paper proposes an innovative approach to compacting the intergranular spaces by treating them with diamond grains finer than the main fraction. To implement this approach, analytical dependencies were derived for the distance between the diamond grains. Intensive wear of the diamond roller bond was observed when the distance was exceeded as a result of contact with the abrasive grains of the grinding wheel. A ratio between the grain sizes of the main and additional diamond fractions is also recommended. Diamond roller dressers made of synthetic diamonds with a medium or high strength and a mixed grit size were created and their wear resistance was studied during the uni-directional and counter-directional dressing of electrocorundum grinding wheels using the plunge-grinding method. Theoretical and experimental models were constructed to predict the lifetime and the wear of diamond rolls in relation to the radial feed rate, the dressing speed ratio, the dress-out time, and the grit size ratio. Multi-objective optimisation based on a genetic algorithm was used to determine the optimal dressing conditions, ensuring the best combination of the maximum lifetime and minimum wear of the diamond rolls. The results obtained confirm the validity and correctness of the proposed approach for increasing the wear resistance of diamond roller dressers. Full article

A multi-strip detector made of synthetic single crystal diamond (SCD), based on a p-type/intrinsic diamond/Schottky metal transverse configuration and operating at zero bias voltage, was developed for imaging from extreme UV (EUV) to soft X-rays. The photodetector was patterned with 32 strips made of boron-doped diamond directly deposited, by means of the CVD technique and the standard lithographic technique, on top of the HPHT diamond growth substrate. The width of each strip and the gap between two adjacent strips were 100 μm and 20 μm, respectively. The strips were embedded in intrinsic SCD of an active area of 3.2 × 2.5 mm², also deposited using the CVD technique in a separate growing machine. In the present structure, the prototype photodetector is suitable for 1D imaging. However, all the dimensions above can be varied depending on the applications. The use of p-type diamond strips represents an attempt to mitigate the photoelectron emission from metal contacts, a non-negligible problem under EUV irradiation. The detector was tested with UV radiation and soft X-rays. To test the photodetector as an imaging device, a headboard (XDAS-DH) and a signal processing board (XDAS-SP) were used as front-end electronics. A standard XDAS software was used to acquire the experimental data. The results of the tests and the detector’s construction process are presented and discussed in the paper. Full article

Technological advances in laboratory-grown diamonds (LGDs) have eroded the scarcity premium of natural diamonds, raising the question of whether diamonds still function as a safe haven. At the same time, crystalline osmium has become investable for the first time, as crystallization technology enables safe storage, certification, and global trading. Using monthly data from 2017–2025, we form diversified portfolios with and without diamonds and with and without osmium, as well as two-asset combinations with the MSCI World. The results show that diamonds no longer provide reliable stability, while osmium consistently contributes to reducing volatility. For portfolio investors, the key lesson is that traditional safe-haven roles can change; diamonds no longer offer robust protection, whereas crystalline osmium acts as a stabilizing component. These findings illustrate the contrasting effects of technological change: substitution and loss of value for diamonds, usability and stabilization for osmium. Full article

This study evaluates the efficiency of sub-stoichiometric Ti₄O₇ titanium oxide anodes for the electrochemical degradation of glyphosate, a persistent herbicide classified as a probable carcinogen by the World Health Organization. After optimizing the process operating parameters (pH and current density), the mineralization efficiency and fate of degradation by-products of the treated solution were determined using a total organic carbon (TOC) analyzer and HPLC/MS, respectively. The results showed that at pH = 3, glyphosate degradation and mineralization are enhanced by the increased generation of hydroxyl radicals (^●OH) at the anode surface. A current density of 14 ${\mathrm{mA} \mathrm{cm}}^{-2}$ enables complete glyphosate removal with 77.8% mineralization. Compared with boron-doped diamond (BDD), ${\mathrm{Ti}}_4{\mathrm{O}}_7$ shows close performance for treatment of a concentrated glyphosate solution (0.41 mM), obtained after nanofiltration of a synthetic ionic solution (0.1 mM glyphosate), carried out using an NF-270 membrane at a conversion rate (Y) of 80%. At 10${ \mathrm{mA} \mathrm{cm}}^{-2}$ for 8 h, ${\mathrm{Ti}}_4{\mathrm{O}}_7$ achieved 81.3% mineralization with an energy consumption of 6.09 ${\mathrm{kWh} \mathrm{g}}^{-1}$ TOC, compared with 90.5% for BDD at 5.48 ${\mathrm{kWh} \mathrm{g}}^{-1}$ TOC. Despite a slight yield gap, ${\mathrm{Ti}}_4{\mathrm{O}}_7$ demonstrates notable efficiency under demanding conditions, suggesting its potential as a cost-effective alternative to BDD for glyphosate electro-oxidation. Full article

An analysis of the existing methods of sintering diamond-containing composites is presented. On the basis of mathematical modeling and experimental studies, the conditions of the laser liquid-phase sintering of diamond-containing composites under which they retain their strength are determined. The energy and technological parameters of the laser irradiation process are characterized, which determine the range of laser processing modes within which no oxidation and crack formation occur, and a high-quality composite with specified geometrical parameters is formed. It has been proven that composites consisting of synthetic diamond grains and a metal bond do not lose strength under the condition that the temperature during laser heating does not exceed 1600 °C and the exposure time is 0.3 s. Electron microscopy and X-ray diffractometry were used for experimental studies of the microstructure and phase composition of the sintered layers. A new design and manufacturing method for a drum-type abrasive tool with replaceable diamond inserts for grinding large-sized aircraft and shipbuilding products are proposed. Components of a laser technological complex for the implementation of the process of sintering the diamond-containing layer of the abrasive inserts of the drum have been developed. Full article

In this study, a boron-doped diamond (BDD) sensor was used to study the electroanalytical behavior of emerging contaminants (ECs), such as caffeine, paracetamol and methyl orange. BDD shows strong resolving power for the superimposed voltammetric response of ECs in well-resolved peaks with increased peak current. Differential pulse voltammetry, which is an electroanalytical technique, was compared with two reference techniques including absorption spectrophotometry in the UV-vis region and high-performance liquid chromatography (HPLC) in the detection and quantification of ECs. The results obtained were satisfactory, as the complete removal of ECs was achieved in all applied processes. The detection limits were 0.69 mg L⁻¹, 0.84 mg L⁻¹ and 0.46 mg L⁻¹ for CAF, PAR and MO, respectively. The comparison of electroanalysis results with those obtained by UV-vis and HPLC established and confirmed the potential applicability of the technique for determining CAF, PAR and MO analytes in synthetic effluents and environmental water samples (tap water, groundwater and lagoon water). The electrochemical approach can therefore be highlighted for its low consumption of reagents, ease of operation, time of analysis and excellent precision and accuracy, because these are characteristics that enable the use of this technique as another means of determining analytes in effluents. Full article

The payload module of a high-throughput satellite involves the complex assembly of various components, which plays a vital role in maintaining the satellite’s structural and functional integrity. To support this, inspections during the assembly process are essential for minimizing human error, reducing inspection time, and ensuring adherence to design specifications. However, the current inspection process is entirely manual. It requires substantial manpower and time and is prone to errors such as missed or false detections, which compromise the overall effectiveness of the inspection process. To enhance the inspection efficiency and accuracy of the payload module in high-throughput satellites, this paper proposes a framework for text detection and recognition targeting diamond labels, R-hole labels, and interface labels within payload module images. Detecting and recognizing text labels on products in the high-throughput satellite payload module provides a means to determine the individual products’ assembly states and the correctness of their connection relationships with the waveguides/cables. The framework consists of two key components: a copy-and-paste data augmentation method, which generates synthetic images by overlaying foreground images onto background images, together with a text detection and recognition model incorporating a dual decoder. The detection accuracy on the simulated payload module data reached 87.42%, while the operational efficiency improved significantly by reducing the inspection time from 5 days to just 1 day. Full article

Water scarcity has driven the use of wastewater treatment plant (WWTP) effluents as reclaimed water, highlighting the need to overcome challenges such as the presence of emerging contaminants, particularly microplastics (MPs), which WWTPs are unable to effectively remove. Membrane-based processes, such as microfiltration, have demonstrated high efficiency in the removal of suspended solids, and their application for MP removal is currently under investigation. This study assesses the influence of microfiltration membrane spacer size (1 mil and 80 mil) and geometry—diamond and corrugated—on MP recovery performance, using synthetic wastewaters with varying MPs concentrations. The results indicate the superior performance of large corrugated and small diamond-shaped membranes, as both exhibited the highest and comparable permeate flux, with no MP retention within the membrane element. All microfiltration membranes achieved an 80% recovery of the influent as safe reclaimed water and demonstrated an MP recovery efficiency exceeding 99%, with 100% rejection for fragments and up to 98% rejection for fibres. Full article

Composite grids serve as reinforcement in concrete structures, offering alternatives to conventional steel reinforcement. These grids can be fabricated from various materials, including synthetic polymers, metals, and natural fibers. This study explores the use of composite grids as lateral confinement of self-compacting concrete (SCC) cylinders and examines their impact on the failure mode under axial compression. In the experiment, the types of grids and mesh shapes used were plastic grids of diamond mesh (PGD) and regular mesh (PGT), metallic grids of diamond mesh (MGD) and square mesh (MGS), vegetable grids of Alfa fiber mesh, 10 × 10 mm (VGAF-1) and 20 × 20 mm (VGAF-2), and vegetable grids of date palm fibers (VGDF). The binder of SCC mixtures incorporated 10% marble powder as a partial replacement for ordinary Portland cement (OPC). SCC mixtures were tested in the fresh state by measuring the slump flow diameter, V-funnel flow time, L-box blocking ratio, and segregation index. Cylinders with a diameter of 160 mm and a height of 320 mm were made to assess the mechanical properties of hardened SCC mixtures under axial compression. The results indicate that most of the confined cylinders exhibited an increase in ductility compared to unconfined cylinders. Grid types MGD and PGD provided the best performance, with ductility increases of 100.33% and 96.45%, respectively. VGAF-2 cylinders had greater compressive strength than cylinders with other grid types. The findings revealed that the type and mesh shape of the grids affects the failure mode of confined cylinders, but has minimal influence on their modulus of elasticity. This study highlights the potential of lateral grid confinement as a technique for rehabilitating, strengthening, and reinforcing weaker structural concrete elements, thereby improving their mechanical properties and extending the service life of building structures. Full article

Diamond is a semiconductor with a large band gap (5.48 eV), high carrier mobility (the highest for holes), high electrical resistance and low capacitance. Thanks to its outstanding properties, diamond-based detectors offer several advantages, among others: high signal-to-noise ratio, fast response, intrinsic pulse-shape discrimination capabilities for distinguishing different types of radiation, as well as operation in pulse and current modes. The mentioned properties meet most of the demanding requests that a radiation detection material must fulfil. Diamond detectors are suited for detecting almost all types of ionizing radiation including X-ray and UV photons, resulting also in blindness to visible photons and are used in a wide range of applications including ones requiring the capability to withstand harsh environments. After reviewing the fundamental physical properties of synthetic single crystal diamond (SCD) grown by microwave plasma enhanced chemical vapor deposition (MWPECVD) technique and the basic principles of diamond-photon interactions and detection, the paper focuses on SCD detectors developed for X-ray and UV detection, discussing their configurations, construction techniques, advantages, and drawbacks. Applications ranging from X-ray detection around accelerators to UV detection for fusion plasmas are addressed, and future trends are highlighted too. Full article