Tungsten Powder Research Articles

Tungsten coating by diffusion on diamond surfaces: process and characterization

Tungsten coating on the diamond surface can significantly enhance the thermal stability, corrosion resistance, and wear resistance of diamond, thereby stabilizing its performance. It can also improve the wettability of diamond with other matrix materials, enhance interfacial bonding, and optimize the properties of composite materials. In this study, high-purity tungsten powder was treated, and a self-made coating material was used to coat a nano-tungsten layer on the diamond surface via diffusion coating. The phase, microstructure, and microscopic defects of the tungsten-coated diamond were characterized and analyzed. The results show that continuous and dense nano-coatings can be formed on the diamond surface through diffusion coating. The main phases of the coatings are W, W₂C, and WC, with the absolute contents of W₂C and WC increasing as the coating time increases. The relationship between coating thickness and coating time transitions from linear to nonlinear with increasing time. The diamond {111} surface typically forms a dense, continuous structure with triangular etched pits, while the {100} surface usually presents a granular junction with square etched pits and a higher degree of etching. Additionally, random, irregular etched pits are observed on the diamond surface. These findings are of great significance for improving diamond properties and are expected to guide the development of diamond surface metallization and the diamond composite material system.

Sustainable processing of tungsten heavy alloys via ultrasonic recycling and aluminum addition: microstructure and mechanical property optimization

This study presents the sustainable preparation and characterization of a novel Class 2 tungsten heavy alloy (WHA) reinforced with varying aluminum (Al) contents (0–4 wt%). High-purity recycled tungsten powder was produced via ultrasonic-assisted acidic leaching and alloyed with nickel (Ni) and iron (Fe) using the powder metallurgy technique. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed phase evolution and significant microstructural refinement. The average tungsten grain size decreased from 17.9 μm (0% Al) to 9.8 μm (4% Al). Density measurements showed that porosity decreased notably at 3% Al content. The 2% Al alloy achieved the highest compressive strength of 2310.8 MPa and excellent ductility, while the 4% Al alloy exhibited superior hardness (36.1% increase) and wear resistance (49.5% improvement). True stress–strain analysis revealed enhanced elastic limits and work-hardening behavior at intermediate Al additions. Moreover, bearing zone percentages, determined via Abbott–Firestone analysis, showed a consistent increase with higher Al contents, indicating improved load-bearing surface characteristics. These findings demonstrate that controlled aluminum alloying significantly enhances densification, microstructure uniformity, and mechanical performance, positioning recycled WHAs as promising candidates for high-stress industrial applications.

Microstructural analysis and characterization of nickel deposition on 316H stainless steel via gas tungsten arc welding and powder laser cladding

Molten salt reactors operate under high-temperature molten salt environments, rendering the use of materials used in traditional pressurized water reactors unsuitable. Therefore, nickel cladding, characterized by excellent corrosion resistance, has been applied to molten salt reactor systems. In this study, the microstructural characteristics and mechanical properties of nickel cladding fabricated using gas tungsten arc welding (GTAW) and powder laser cladding (PLC) were examined. The GTAW process yielded a cladding with excellent mechanical performance and no internal defects. However, extensive intergranular corrosion was observed after a 100-h immersion test, attributable to the presence of high-energy grain boundaries. Conversely, the PLC specimen exhibited cracks and porosity. However, the presence of low-energy grain boundaries contributed to uniform corrosion behavior and enhanced corrosion resistance. These findings underscore the complementary advantages and limitations of both techniques, highlighting the necessity for further optimization to ensure reliable performance in high-temperature reactor environments.

Accelerated sintering and microstructural regulation of tungsten powder compact by novel modulation of particle configuration

Accelerated sintering and microstructural regulation of tungsten powder compact by novel modulation of particle configuration

Research on combustion characteristics of new high energy composite materials − using tungsten powder as fuel and DAP-4 as oxidizer

Research on combustion characteristics of new high energy composite materials − using tungsten powder as fuel and DAP-4 as oxidizer

Multi-scale numerical modeling of inductively coupled plasma spheroidization of refractory tungsten powders for additive manufacturing

Multi-scale numerical modeling of inductively coupled plasma spheroidization of refractory tungsten powders for additive manufacturing

Unique approaches in developing novel nano-composites: Evaluating their mechanical and tribological characteristics

Abstract In this study, aluminium surface nano-composites were made by adding secondary phase reinforcement powder particles to the surface and sub-surface layers using friction stir processing (FSP). The study examines the development and tribological properties of aluminium-based surface nano-composites. Initial processing of tungsten (W) and aluminium-oxide (Al2O3) elemental powders involved high-energy ball milling to minimize particle size. After 25 h of milling, the tungsten grain size was 5 nm, while aluminium-oxide was 11 nm after 32 h. FSP was used to integrate these nanostructured reinforcement particles into the aluminium matrix. Hardness and wear tests were performed on these composites. From base to processed, composite hardness increased. More tool passes improved hardness and wear. The friction stir processed (FSPed) second-pass aluminium–tungsten specimen has 96 times greater wear resistance than the base material. The FSPed second-pass specimen of aluminium–tungsten surface composite, which had maximum wear resistance, was depth-sensing nanoindented at various peak loads and loading rates. Nano-hardness was 1.56 ± 0.33 to 1.26 ± 0.15 GPa (420 ± 3 MPa for base material). Elastic modulus readings were 93 ± 1 to 72 ± 1 GPa (70 ± 1 for base material).

MODELING AND EXPERIMENTAL STUDIES OF THE CHEMICAL VAPOR INFILTRATION PROCESS OF TUNGSTEN SELF-COMPOSITES

The numerical modeling using the COMSOL Multiphysics software of the process of chemical vapor infiltration of tungsten powder in order to establish the dependences between the residual porosity of the self-composite and the synthesis parameters was carried out. The influence of the parameters of the chemical vapor infiltration process of tungsten powder on the depth of its impregnation and the density of the resulting selfcomposites was experimentally studied also. It has been established that the main factor determining the maximum depth of infiltration is the rate of deposition of tungsten from the gas phase.

X-Ray imaging method for in-situ study of particle-laden flows

The accurate measurement of flow parameters often depends on sensor accessibility. Optical flow assessment techniques, such as Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV), are limited to optically transparent media. However, many industrial processes involve opaque media, necessitating alternative methods. This study presents the development and application of X-ray Particle Tracking Velocimetry (XPTV) to investigate flows within such media. Specifically, the flow inside a nozzle of a Fused Filament Fabrication (FFF) printer was examined. A novel contribution of this work is the first-time analysis of heated flow using XPTV, achieved by introducing tungsten powder as a contrast agent in the polymer flow. The study successfully visualized a parabolic velocity profile, demonstrating the method’s efficacy.

A simultaneous X-ray fluorescence and diffraction analysis method for internal depth profile probing of the volume of material

A simultaneous X-ray fluorescence (XRF) and X-ray diffraction (XRD) analysis method for probing the internal depth profile of a material using tungsten target and cadmium telluride (CdTe) detectors is presented. To select a suitable target source, a Geant4 simulation is used to simulate the characteristic X-ray photon numbers produced by metallic materials with atomic numbers ranging from 24 to 92. The fluorescence analysis demonstrates the ability to measure intensity-depth profiles to greater than 500 μm depth in CeO2 powder, at least 400 μm depth in Er2 O3 powder, at least 200 μm depth in WO3 powder and up to 500 μm depth in Bi2 O3 powder. In addition, the diffraction analysis demonstrates the capacity to measure intensity-depth profiles to a depth of greater than 5 mm in silicon powder, at least 2 mm depth in nickel powder and up to 200 μm depth in tungsten powder. This method could be extended to component and phase detection in the safety inspection of flammable and explosive materials.

The influence of the fluoride process of tungsten deposition parameters on the properties of tungsten self-composites obtained by chemical vapor infiltration

The influence of the parameters of the chemical vapor infiltration process of tungsten powder on the depth of its impregnation, mechanical properties and density of the obtained blanks is studied. It was found that the depth of infiltration depends on the rate of chemical vapor deposition of tungsten, and the maximum bend strength is achieved the sample, obtained at temperature of 450 °C and a gas pressure of 133 mbar. The method of chemical vapor infiltration is promising for the development of technology of additive manufacture of the items made of tungsten and composites based on it.

Rheological analysis of cemented carbides and Tungsten powders for additive manufacture via laser powder bed fusion technique

In Additive Manufacturing (AM) using the Laser Powder Bed Fusion (L-PBF) technique, spherical powders are the most commonly preferred for direct sintering. However, composites such as cemented carbides and heavy alloys often exhibit irregular shapes. Due to the requirement for extremely fine grain size, the cohesive behavior of the particle bed becomes significant, influencing its compressibility and porosity. These physical properties result in powders with coarse textures, which lead to low fluidity and interruptions in material flow within the ducts. This study evaluates the flowability of WC and W refractory materials combined with Co and Ni. Key interparticle properties, including real and bulk density, bulk compressibility and porosity, and granular shear, were analyzed to understand their influence on the deposition layer behavior in the powder bed. These parameters are crucial for understanding the micro-behavior of granular materials and correlating it with their macro-behavior. The rheological aspects of these composite powders are discussed, aiming to establish correlations between the manufacturing process and the resulting properties of their mixtures.

Повышение стойкости зубьев буровых долот за счет изменения технологии их изготовления

Introduction. The development of the mining industry requires increasing the durability and safe tool performance life. For bits of mining drilling machines, this problem is often solved by improving the material of the teeth of these bits. The paper presents the results of a study on the development of a technology for the manufacture of hard-alloy drill bits with increased wear resistance and testing of prototypes when drilling hard rocks. Changes in technology have led to changes in the shape of the tooth. Also, purer tungsten powder was used as the initial component. Research methods. The paper studies carbide teeth of bits manufactured at JSC Almalyk Mining and Metallurgical Combine using standard and modified technology. Its structure and chemical composition were studied. Results and discussion. New methods for performing technological operations for the manufacture of carbide teeth (pins) and steel pin bits are developed and mastered. Tungsten-cobalt teeth were manufactured using VK10KS (90 %W; 10 % Co) hard alloy, produced using tungsten carbide powder synthesized by carbidization of purified tungsten powder. The shape of the tooth surface was changed from ballistic to semi-ballistic. Metallic cobalt powder was used as a binder. Pin bits of the KNSh40×25 type are made of 0.35 C-Cr-Mn-Si steel. Tests of experimental bits were carried out at several mines, as a result of which its suitability for drilling rocks with a hardness of f` = 14–18 was established. The results of industrial operation showed that the durability of the teeth of bits manufactured by JSC Almalyk Mining and Metallurgical Combine is not significantly inferior to bits from European manufacturers. At the same time, the cost of such bits is several times lower.

Electron microscopic analysis of a metal layer deposited with tungsten-containing powder wire

The effect of replacement of powdered tungsten and graphite in flux-cored wire with tungsten oxides and carbon-fluorine-containing material during surfacing with flux-cored wire on the qualitative characteristics of the deposited metal layer was investigated by scanning electron microscopy methods. The metal of the sample with metallic tungsten powder has a dendritic structure and is distinguished by a pronounced diversity of grain. The grains are large, irregularly shaped, ranging in size from 30 to 150 μm. The microstructure of the sample is biphasic and consists of a solid solution of tungsten in iron and an intermediate phase. The tungsten concentrate sample metal has a more uniform microstructure. Grains are equiaxial, almost regular octahedral in shape. The grain size corresponds to 1.5 points ac-cording to GOST 5639–82 (the average grain diameter is 200 μm). The structure of the sample is single-phase, it is a solid solution of tungsten in -iron, similar to the needle-like structure of Widmatstätt ferrite with a border of free ferrite in iron-carbon steels. The deposited metal of both samples is characterized by a high degree of purity in terms of non-metallic inclusions. In a steel sample using tungsten metal, globular inclusions of aluminosilicates and point inclusions of iron and tungsten oxides were found. In a sample of steel using a tungsten concentrate with a reducing agent, non-metallic inclusions of a complex composition based on oxides of iron, tungsten and manganese sulfides predominate during surfacing and non-metallic inclusions of a complex composition based on manganese sulfides and aluminosilicates

Study on the integrated technology of arsenic removal and tungsten extraction based on the formation and decomposition of arsenotungstic acid

Study on the integrated technology of arsenic removal and tungsten extraction based on the formation and decomposition of arsenotungstic acid

Investigation of damage on FeCr26Ni36Co15W5 alloy reduction furnace tube during service

ABSTRACT The microstructure and mechanical properties of tungsten powder reduction furnace tube are investigated in this work. After service, the lamellar and skeleton-shape primary carbides of FeCr26Ni36Co15W5 alloy coarsened and formed a continuous network, much fine secondary carbide precipitated in the dendrite interior. The tensile strength and ductility of FeCr26Ni36Co15W5 alloy decreased. And, the creep strength of FeCr26Ni36Co15W5 alloy has reached the end of the service life. Meanwhile, the corrosion products were studied by XRD and XRF. It was found that the corrosion products were Na2WO4·2 h2O, Na2CO3·H2O and Cr4Ni15W，and the evaporation of catalyst (Na2CO3) results in a large amount of Na2CO3·H2O in the corrosion products. The hot corrosion mechanism of the reduction furnace tube is Type I hot corrosion.

Аналіз процесу ущільнення порошків вольфраму плакованих міддю

The paper analyzes the pressing process of a composite powder of the tungsten-copper system using the basic mathematical equations describing the deformation processes of a porous body as a function of density and pressing pressure. Several theoretical dependences describing different pressing mechanisms are considered, taking into account modern approaches, namely the discrete-contact model and the continuum model of a continuous medium. The most well-known equations, including those of Balshin M.Y., Zhdanovich G.M., and Shtern M.B., are analyzed. It is established that most of them have limited applicability, remaining valid for individual stages of the pressing process and significantly depend on the mechanical properties of the material that determine the predominance of elastic or plastic deformation. At the same time, most equations are focused on single-component powders, which does not correspond to the practice of powdered parts production processes. To test the theoretical dependencies, copper-clad tungsten powder was obtained by chemical vapor deposition from solution. The technological parameters of the cladding process (composition, solution concentration, and deposition time) that determine the quality of the resulting coatings were determined. The morphology of the particles of clad powders and the structure of tungsten-copper pressings were investigated. It is shown that tungsten powder forms a relatively dense framework with a copper layer, respectively, the structure of composite powder pressings is as close as possible to a continuous continuum and is correctly described by an equation based on the theory of continuity of the medium, It has been established that the compaction character of copper-clad tungsten powder differs from that of single-component tungsten powder, which is due to the fact that plastic deformation mechanisms prevail for tungsten-copper composite powders.

Production and research of tungsten carbide powder from VA grade tungsten metal waste in aviation kerosene

Purpose. Obtaining and studying the composition, structure and properties of tungsten carbide powder from VA grade tungsten metal waste in aviation kerosene. Methods. Tungsten carbide powder from tungsten metal waste of the VA brand was obtained in the following sequence. The reactor was filled with a working medium – aviation kerosene of the TS-1 brand, the waste was loaded into the reactor. Electrodes were mounted from the same waste tungsten of the VA brand. The mounted electrodes were connected to a pulse generator. The necessary electrical parameters of the installation were set: the capacitance of the condensers is 42.0–43.5 UF; the voltage on the electrodes is from 115–120 V; the pulse repetition rate is 50–55 Hz. The resulting tungsten powder was studied using: a scanning electron microscope QUANTA 600 FEG; a particle size analyzer Analysette 22 NanoTec; an energy-dispersed X-ray analyzer from the company EDAX; X-ray diffraction on a diffractometer Rigaku Ultima IV. Results. Based on the conducted experimental studies, a new method for producing tungsten carbide powder has been developed, characterized in that the powder is obtained by electroerosive dispersion of tungsten metal waste of the VA brand in aviation kerosene at a capacitor capacity of 42.0–43.5 UF, an electrode voltage of 115–120 V and a pulse repetition frequency of 50–55 Hz. It has been experimentally established that spherical and elliptical particles of tungsten carbide powder W2C have sizes from 2.26 microns to 90.72 microns with an average volumetric diameter of 20.2 microns and contain carbon on the surface. Conclusion. The production of tungsten carbide suitable for industrial use at low energy costs from metal waste has shown high efficiency of the technology of electroerosion dispersion.

Effect of Ball Milling Parameters on Properties of Nano-Sized Tungsten Powder via Mechanochemical Processing

Nano-sized tungsten exhibits superior properties due to its high-density grain boundaries’ strengthening. The high-quality nano-sized powder is essential for sintering nano-sized tungsten bulks through powder metallurgy techniques. In this study, nano-sized tungsten powder was successfully synthesized by mechanochemical methods using mixed WO3 and Mg powders. The effects of processing parameters on the morphology and microstructure of synthesized powder were thoroughly investigated. The results reveal that the thermite reaction of WO3 and Mg is almost complete after 5 min of ball milling at a speed of 300 rpm. The average grain size of the tungsten powder decreases with the increasing milling duration and speed. Optimal average grain size and purity were achieved at a milling speed of 300 rpm and a milling duration ranging from 30 to 120 min. Moreover, centrifugation sieving further reduces the average grain size of tungsten powder to 19.5 nm. In addition, the entire mechanochemical process can be divided into two stages: the reaction stage and the grain size refinement stage.

Advanced Electrospun Composites Based on Polycaprolactone Fibers Loaded with Micronized Tungsten Powders for Radiation Shielding.

Exposure to high levels of radiation can cause acute, long-term health effects, such as acute radiation syndrome, cancer, and cardiovascular disease. This is an important occupational hazard in different fields, such as the aerospace and healthcare industry, as well as a crucial burden to overcome to boost space applications and exploration. Protective bulky equipment made of heavy metals is not suitable for many advanced purporses, such as mobile devices, wearable shields, and manned spacecrafts. In the latter case, the in-space manufacturing of protective shields is highly desirable and remains an unmet need. Composites made of polymers and high atomic number fillers are potential means for radiation protection due to their low weight, good flexibility, and good processability. In the present work, we developed electrospun composites based on polycaprolactone (polymer matrix) and tungsten powder for application as shielding materials. Electrospinning is a versatile technology that is easily scalable at an industrial level and allows obtaining very lightweight, flexible sheet materials for wearables. By controlling tungsten powder size, we engineered homogeneous, stable and processable suspensions to fabricate radiation composite shielding sheets. The shielding capability was assessed by an in vivo model on prototype composite sheets containing 80 w% of W filler in a polycaprolactone (PCL) fibrous matrix by means of irradiation tests (X-rays) on mice. The obtained results are promising; as expected, the shielding effectivity of the developed composite material increases with the thickness/number of stacked layers. It is worth noting that a thin barrier consisting of 24 layers of the innovative shielding material reduces the extent of apoptosis by 1.5 times compared to the non-shielded mice.