Tungsten Carbide Content Research Articles

Performance and Formula Optimization of Graphene-Modified Tungsten Carbide Coating to Improve Adaptability to High-Speed Fluid Flow in Wellbore

In order to improve the erosion resistance of steel PDC (Polycrystalline Diamond Compact) bit under high-speed fluid flow conditions underground, it is necessary to develop a high-performance erosion-resistant coating. In this paper, laser cladding was used to prepare the new coating by modifying tungsten carbide with graphene. And the effects of tungsten carbide content and graphene content on the coating performance have been thoroughly studied and analyzed to obtain the optimal covering layer. The research results indicate that, for new coatings, 60% tungsten carbide and 0.3% graphene are the optimal ratios. After adding tungsten carbide, the hardness has significantly improved. However, when the tungsten carbide content further increases more than 30%, the increase in hardness is limited. In addition, when the content of graphene is more than 0.3%, the branched structure becomes thicker. In detail, this is a phenomenon where the segregation of Cr, Si, and W becomes very obvious again, and the segregation of Fe occurs at the Ni enrichment site. The research results contribute to the development and optimization of high-quality erosion-resistant coatings under the high-speed flow conditions in wellbore. These are of great significance for improving the efficiency of oil and gas exploration and development.

Optimization of structure and properties of WC-reinforced FeCoNiCr high-entropy alloy composite coating by laser melting

High entropy alloys have the potential to be used as coating materials in many fields due to their excellent mechanical properties, corrosion resistance and high-temperature stability. Based on the application requirements of high-entropy alloys, this study aims to explore how tungsten carbide can optimize the properties of high-entropy alloys. Through theoretical research and experimental validation, the effects of the organizational structure of high-entropy alloy coatings on their properties and the effects of tungsten carbide content on the properties of high-entropy alloy coatings were investigated. The micro hardness of the coatings is relatively high at low power laser melting, while it decreases with the increase of laser power. After laser melting of different materials, the average impact toughness of the studied materials exceeded 70 J/cm2, and the average values of microhardness of the optimized coatings prepared at laser powers of 1400 W and 1600 W were more than 160 HV0.2. In addition, the properties of the high-entropy alloys were significantly improved when the content of tungsten carbide reached a certain percentage. The composite coatings have excellent wear resistance, corrosion resistance and thermal stability. Overall, the optimized tungsten carbide on high entropy alloys in this study has good performance, which is of great theoretical and practical significance for understanding the performance regulation and optimal design of high entropy alloy coatings.

Metastable FeCrMnCo HEAs with the reinforcement of tungsten carbide fabricated by laser melting: Microstructure, mechanical properties and tribological behaviors

Fe50Mn30Co10Cr10 high entropy alloy (HEA) can be considered as a candidate structural and functional material, but the early failure during friction with heavy load can limit its more extensive applications. In this paper, a series of tungsten carbide particle reinforced Fe50Mn30Co10Cr10 HEAs were fabricated by laser cladding technique, the influence of tungsten carbide content on microstructure, mechanical properties and tribological behaviors were explored systematically. The results indicated that the dissolution and diffusion of tungsten carbide could contribute to a wettability between tungsten carbide and HEA matrix, and grain refinement was caused by increasing tungsten carbide. The UTS and EL of the P10 sample are increased by simultaneously by 26.8% and 31.1% compared with UTS of 696 MPa and EL of 15.1% for P5 sample. UTS and EL were enhanced simultaneously owing to fine-grained strengthening and nanoscale precipitate strengthening. But higher content of tungsten carbide could cause lower elongation owing to the embrittlement of the materials. Just as this, Rockwell hardness and friction coefficient has an increasing trend with increasing tungsten carbide when an opposite trend exists in volume wear rate. It can indicate that hardness is a more important factor for wear resistance, and excellent wear resistance with 1.25 × 10−5 mm3/(N·m) appear in higher-content WCp reinforced HEA composite. Furthermore, wear mechanism is transformed from abrasive wear in low-content tungsten carbide to adhesive wear in high-content tungsten carbide.

Spark Plasma Sintering of Electric Discharge Machinable 1.5Yb-1.5Sm-TZP-WC Composites

Electrically conductive zirconia tungsten carbide composites are attractive materials for manufacturing precision components by electrical discharge machining due to their high strength, toughness and electrical conductivity. In this study, nanocomposite ceramics with a ytterbia samaria co-stabilized zirconia 1.5Yb-1.5Sm-TZP matrix and 24–32 vol.% tungsten carbide dispersion were manufactured by spark plasma sintering (SPS) at 1400 °C for 15 min at 60 MPa pressure. The materials exhibited high strengths of 1300–1600 MPa, a moderate fracture resistance of 6 MPa√m and an ultrafine microstructure with grain sizes in the 150 nm range. Scanning electron microscopy and RAMAN spectroscopy revealed the in situ formation of carbon during the SPS process and carbon formation scales with tungsten carbide content, and this apparently impedes bending strength.

Особенности формирования фазового и элементного состава при электроискровом легировании ручным вибратором повышенной частоты

The phase and elemental compositions of electrospark coatings of nickel and titanium deposited on steel, nickel, and titanium, that is, coatings from TiNiMo-20 and WC92-Co8 on steel at high-frequency electrospark alloying are investigated. It is established that the material of the electrode, of the substrate, and the mode of deposition have the main impact on physical and chemical properties of the formed coatings. A positive influence of high-frequency alloying on quality indicators of the processed surfaces is shown. Both the phase and chemical analyses showed availability of the compounds considerably improving corrosion resistance of the processed surfaces. Alloying with WC92-Co8 electrodes at a high frequency makes it possible to obtain an increased content of tungsten carbide in the deposited layer.

3D plasma metal deposition for processing multi material Titanium parts

ABSTRACT Within this study, the potential of 3D Plasma Metal Deposition (3DPMD) for the additive manufacturing of multi-material metallic parts in layerwise design is presented. For this purpose, a demonstrator geometry with a step-wise increase of the tungsten carbide content in a Ti6Al4V matrix was fabricated. The build cycle itself, the component shape and the microstructure were investigated. The analysis of the macroscopic properties was performed by optical microscopy and scanning electron microscopy. In summary, 3DPMD offers the possibility to produce AM parts at high build rates and increased material flexibility. The analysis of the morphology and the macroscopic investigations shows a homogenous structure without defects. The carbide content of the manufactured components increases continuously from 0 to 12 vol.% but deviates from the aimed carbide content. Using automated CAM routines, it is possible to generate metallic multi-material structures using welding robots directly from the CAD drawings.

Formation of Cemented Tungsten Carbide Layer with Compositional Gradient Processed by Directed Energy Deposition

In order to partially improve the wear resistance for dies and jigs, layer-forming technologies for adding cemented tungsten carbide is effective way as an additive manufacturing technique. As one of the layer-forming technologies, directed energy deposition (DED) has attracted much attention from industry. However, many cracks are usually observed inside a formed layer processed by the DED due to the difference of material properties between an iron-based substrate and a cladded cemented tungsten carbide layer. In terms of durability of the formed layer, the crack formation is not preferable as well. In this study, as an attempt to suppress the crack initiation and propagation in cladded layers processed by the DED, formation of compositionally graded cemented tungsten carbide layer was performed by inserting a layer with low to medium tungsten carbide content between the substrate and cemented tungsten carbide layer. At first, single layers of cemented tungsten carbide having various tungsten carbide content were formed on iron-based substrates by the DED processing to understand the relationships between the tungsten carbide content and the number of formed cracks. By considering these experimental results, the compositionally graded cemented tungsten carbide layers were optimized. It was revealed that the crack initiation and propagation could be suppressed by compositionally graded cemented tungsten carbide layers.

Электроискровое нанесение порошка карбида вольфрама на титановый сплав Ti6Al4V

Titanium alloys are attracting the attention of researchers and engineers because of their unique combination of high specific strength, corrosion resistance and biocompatibility, but they are characterized by high wear. Therefore, the study of new methods for making protective coatings on titanium alloys is relevant. A mixture of titanium granules with tungsten carbide powder was used to prepare coatings on the titanium alloy Ti6Al4V by the method of electrospark granules deposition. Three mixtures of granules with a tungsten carbide content of 2.1, 4.1 and 6.0 vol.% were prepared. According to the data of X-ray analysis, it was found that the following phases were observed in the composition of the coatings: WC, W2C, W, αTi and β-(W, Ti)C1−x. Carbides W2C, (W, Ti)C1−x and metallic tungsten were formed as a result of the decarburization of WC upon its interaction with molten titanium under the conditions of an electric discharge. Large inclusions of tungsten carbide surrounded by a metallic Ti-W-C binder were observed in the microstructure of the coatings. According to the data of energy dispersive analysis, the concentrations of tungsten and carbon decreased when scanning from the surface layers of the coating to the substrate. The average values of the microhardness of the coatings increased from 7.9 to 9.2 GPa with an increase in the concentration of WC powder in the mixture of granules. The average values of the friction coefficients of the coatings were in the range of 0.33 – 0.48, which is 35 ± 3 % lower than that of the Ti6Al4V alloy. Tests for wear in the dry friction mode at loads of 25 and 70 N showed that the wear rate of the coatings ranged from 0.38 ×10−5 to 1.68 ×10−5 mm3 / Nm. The best wear resistance under both loads was demonstrated by the coatings deposited with the addition of 4.1 vol.% WC, which make it possible to increase the wear resistance of the Ti6Al4V alloy up to 18 times. Thus, the prospect of electrospark deposition of cermet coatings with enhanced mechanical properties on a titanium alloy using tungsten carbide powder mixed with titanium granules is shown.

Effect of CeO2 concentration on the microstructure and wear behavior of Co–WC composites

A novel tungsten carbide (WC)- and ceria (CeO2)-reinforced cobalt (Co) matrix composite coating was synthesized through a one-step co-electrodeposition method. The growth mechanism of the coating and the formation mechanism of the protrusion and gully structure on the coating surface were explored. Furthermore, the mechanism of the influence of ceria concentration on the deposition rate and content of tungsten carbide is discussed. The results revealed that the coating fabricated at 6 g/l ceria achieved a dense structure, a fine grain size, a high content of tungsten carbide (19.9 wt.%) and a high deposition rate (78.2 μm/h). The average thickness of the coating was 118.48 μm, and the composite coating had a preferred orientation of cobalt (101) texture. In addition, the maximum microindentation hardness of the coating deposited at 6 g/l ceria was obtained as 627 HV. The electrodeposits possessed a superior anti-wear behavior, which was mainly ascribed to the synergistic effect of tungsten carbide and ceria in improving the mechanical properties of the cobalt matrix composite coating.

Corrosion Resistance of Nickel-Based Composite Coatings Reinforced by Spherical Tungsten Carbide

Nickel-based composite coatings reinforced by spherical tungsten carbide were deposited on 42CrMo alloy steel using plasma transfer arc welding (PTAW) process. Their electrochemical corrosion properties in NaCl solution under atmospheric and high pressure were studied by polarization curve, electrochemical impedance spectroscopy. The corrosion and erosion resistance of the coatings were also investigated by salt spray corrosion and erosion corrosion tests. The results show that the self-corrosion potential of the composite coatings increased with the increase of tungsten carbide content, and the Cr element in Ni60 sample formed a stable and compact passivation film. Compared with corrosion at atmospheric pressure, the adsorption and penetration of Cl- on the coating surface enhanced due to the increase of Cl- activity under pressure, thereby to weaken the corrosion resistance. The Samples that passivated in salt spray environment, cannot completely hinder the corrosion of the coating, just only to slow down the corrosion. This study can provide theoretical basis for deep-sea oil drilling and production engineering equipment.

THE INFLUENCE OF TECHNOLOGICAL PARAMETERS OF LASER SURFACING ON THE PROPERTIES OF NiCrBSiC-WC COMPOSITES

It was investigated the influence of technological parameters of laser cladding on the thickness of the carbide composite coatings with similar composition and properties of matrix and different types of reinforcing inclusions (spherical tungsten carbides (WC) and recycled carbides). Special attention is paid to physical-mechanical and service properties of the composites such as hardness and resistance to abrasive wear. It is established that the thickness of the carbide composite coatings increases with increasing laser power and flow rate of the carrier gas, and with decreasing speed of the laser and the step of cladding. The study showed that at the addition of 50 wt.% WC matrix has smaller hardness values 540-560 HV, which allows to obtain the structure of the carbide composite coatings without cracks. At the same time, at addition of 80 wt.% WC matrix has higher hardness 670 HV, which does not provide the structure without cracks. Resistance of composites NiCrBSiC-WC to cracking, as well as their wear resistance, increases with increasing content of tungsten carbide. The wear resistance of the coatings received from powder Technicord 655-SL, with a reinforcement by recycled carbide, comparable to that for coatings from spherical tungsten carbide Tekmat WC-125. Coatings NiCrBSiCWC, obtained by laser cladding, are used to increase the service life of the equipment telemetering systems, in particular, it is possible to prevent of abrasion and provide of increasing the service life of the contact pads of the equipment for measurement while drilling.

Functional Layers of Aluminium Alloy on Steel Made by Alternative Friction Processes, for Elements of Metal Structures

Coating of steel with aluminium alloy is needed for the execution of a functional layer for corrosion protection. Some experiments have been performed on square-section tubes (50 mm x 50 mm) of S235 steel, according to EN 10 025, to be coated with 1 mm thick sheets of EN AW 5754 aluminium alloy that have been previously bended as U shaped profiles. A new experimental model of specialized equipment has been used for certain experiments to make these functional layers of aluminium alloy on steel. Firstly, friction drilling and threading by form tapping, followed by screws-mounting without nuts have been used to make such joints. Several holes have been executed by a Ø4.3 friction drilling tool, then an M5 form tap was used for threading. For friction drilling, tools with 90% tungsten carbide content and 1 micron grain size were applied. By threading, TiN coated form taps have been used. Secondly, overlap friction stir welding (FSW) has been applied, to make a functional layer of aluminium alloy on a 50 mm x 50 mm S235 steel tube. The wings of the U profiles were overlapped. A quenched FSW tool, own-made of C 45 grade steel, EN 10083, has been used for these joining tests. The joining parameters are mentioned for each process. The run of each joining process is described and the joint test samples are presented. The appearance of the screw-mounted functional layers is appropriate. The metallographic analysis has revealed adequate form of the burr formed below the hole. The burr height is 2.5 – 3.2 mm. The pattern of the M5 thread is appropriate. No defects have been detected on the holes and threads. The appearance of the FSW functional layers is adequate. Metallographic analysis shows that FSW joints of the overlapped aluminium alloy sheets are adequate, because there is no gap between these sheets. There is only a narrow gap between the aluminium alloy bottom sheet and the wall of the steel tube, which proves an appropriate positioning of the two metals. No defects were detected, except for a weld flaw, as a small and isolated cavity, with a section less than 0.1 mm2, considered within the acceptance limit, according to EN 25239-5. The U shaped sheets of aluminium alloy are firmly fixed on the square steel tube, for both coating types. The mentioned processes are proposed to increase productivity in industrial technologies for series production. The processes addressed in this paper are more rapid than conventional processes. Adequate preparation of the parts to be welded, mechanization and automation allow repeatability and quality. The target applications are coated structure elements for devices, appliances, tools, welded structures or automobiles. The involved industrial areas of the applications are: manufacturing, electro-technique, construction and automotive industries. The presented processes are ecological, because they do not need lubricants or other toxic substances and do not produce chips or harmfull substances.

Investigation of Micro-structure and Mechanical Behaviour of Aluminum - Zircon Sand - Tungsten Carbide Metal Matrix Composites

Nowadays composites play a vital role in automotive and aircraft applications. The main objective of this work is to employ aluminum-zircon sand – tungsten carbide metal matrix composites as they possess light in weight characteristics with improved corrosion and hardness properties. The casting was made up with stir casting and the mechanical properties are studied. This paper deals with the investigation of effects of zircon sand and tungsten carbide as reinforcements in aluminum metal matrix composite. The results show that tensile strength of composite increases with increase in percentage of tungsten carbide from 0.5 % to 1.5 %. But, when it is 2% there is reduction in strength due to higher content of tungsten carbide. Similar to tensile test results, compressive load also increases up to 1.5%. The impact test reveals that the energy absorbed by all the composites is similar to each other. The hardness test proves that the hardness of the alloy decreases with increase in the alloying content. Morphological analysis is carried out to find the internal structure of the tested specimens.

Facile synthesis of tungsten carbide-carbon composites for oxygen reduction reaction

Tungsten carbide-carbon composite (XWC-C, where X=10 or 30 represents the tungsten content) supports were prepared by pyrolyzing tungsten-adsorbed poly(4-vinylpyridine)-functionalized carbon. The supports were used to prepare Pt catalysts (Pt/XWC-C) for oxygen reduction reactions (ORR) in alkaline solution. Prepared XWC-C revealed highly dispersed tungsten carbide species composed of WC and W2C phases. The tungsten carbide species proved to have a positive effect on the dispersion of Pt particles. Compared to the Pt catalyst supported on carbon (Pt/ C), Pt/XWC-C showed higher ORR performance. In addition, the catalytic performance of Pt/XWC-C was enhanced with increasing tungsten carbide content. The highest ORR activity was achieved for the Pt/30WC-C catalyst, which had a 2.9-fold enhanced performance (at 0.8V vs. RHE) compared to that of Pt/C. It is believed that the unique interaction between Pt and the tungsten carbide species was responsible for the enhanced ORR performance of the Pt/XWC-C catalysts.

Microstructures and Wear Performance of PTAW Deposited Ni-Based Coatings with Spherical Tungsten Carbide

The Ni-based coatings with different content of spherical tungsten carbide were deposited by plasma transfer arc welding (PTAW) method on 304 austenitic stainless steel sheets in this study. The microstructure and wear property of spherical tungsten carbide particle reinforced composite coatings were investigated by means of optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA) and sliding wear test. It is shown that the fraction of spherical tungsten carbides has an important influence on microstructure of Ni-based overlay. The Ni40 overlay consists of γ-Ni dendrites with interdendritic Ni-based eutectics, borides and carbides improving the wear resistance. In the case of composite coatings with different content of tungsten carbide, many new phases are observed, such as Ni2W4C and NiW. In addition, there are a large number of irregular structures in composite coatings, such as acicular structure and irregular stripe organization. The results of sliding wear test indicate that the mass loss of coatings is influenced by the content of tungsten carbide. The mass loss decreases with the increase of tungsten carbide fraction. At high load, the abrasive resistance of composite coating with 60 wt. % tungsten carbide is improved about 50-fold compared to that of Ni40 overlay.

Friction Force Microscopy Analysis of Self-Adaptive W-S-C Coatings: Nanoscale Friction and Wear.

Transition metal dichalcogenides (TMD) are increasingly popular due to unique structural and mechanical properties. They belong, together with graphene and similar 2D materials, to a small family of solid lubricants with potential to produce ultralow friction state. At the macroscale, low friction stems from the ability to form well-oriented films on the sliding surface (typically up to 10 nm thick), with the TMD basal planes aligned parallel to the surface. In this study, we quantitatively evaluate tribological properties of three sputtered tungsten-sulfur-carbon (W-S-C) coatings at a nanoscale using friction force microscopy. In particular, we investigate possible formation of well-ordered tungsten disulfide (WS2) layers on the coating surface. The coefficient of friction decreased with increasing load independently of coating composition or mechanical properties. In contrast, hard coatings with high tungsten carbide content were more resistant to wear. We successfully identified a WS2 tribolayer at the sliding interface, which peeled off as ultrathin flakes and attached to AFM tip. Nanoscale tribological behavior of WSC coatings replicates deviation of Amonton's law observed in macroscale testing and strongly suggests that the tribolayer is formed almost immediately after the start of sliding.

Effect of titanium and tungsten carbide on the formation of the structure and the properties of composite coatings. Part 1: the structure and phase composition of steel R6M5–(WC+TiC) coatings

The results of investigations of the special features of the formation of the structure and phase composition of R6M5 steel–(WC+TiC) composite coatings in relation to the content of tungsten monocarbide in the initial charge are presented. It is shown that the amount of retained austenite in the composite coating depends on the tungsten carbide content in the total volume of the added hardening phase. The maximum amount of austenite (75%) in relation to the total volume of the matrix was observed in the coatings containing 20% of the carbide component.

Influence of laser cladding process on the magnetic properties of WC–FeNiCr metal–matrix composite coatings

Metal–matrix composite (MMC) coatings were deposited by laser cladding technique with direct injection of WC–FeNiCr powder onto N1310 nonmagnetic steel matrix. Laser cladding was conducted using a Trumpf6000 CO2 laser. The morphology of WC–FeNiCr MMC coatings was characterized using scanning electron microscopy (SEM). Magnetic properties of WC–FeNiCr MMC coatings were examined by vibrating sample magnetometer (VSM) at room temperature. The influence of laser cladding process on the magnetic properties of coatings was investigated. It was found that the content of tungsten carbide and laser power have significant effect on the magnetic properties of composite coatings. The evolution of phase constitution at different laser power was identified by X-ray diffraction (XRD). The presence of an austenitic γ-(Fe, Ni), Cr0.19Fe0.7Ni0.11, Fe3W3C, WC and W2C phases were confirmed by the XRD analysis in the laser clad layer.

Wear behaviour of tungsten carbide particles reinforced copper alloy composites

The wear behaviour of copper alloy (phosphor–bronze) composites was studied as a function of sliding speed and applied loads. Loads of 20 to 160 N in steps of 20 N and linear speeds of 1.25, 1.56, and 1.87 m/s were employed. The results indicated that wear rate of both the composites and the alloy increased with increase in load and sliding speed. However, the composites exhibited lower wear rate than the alloy. It was found that above a critical applied load, there exists a transition from mild to severe wear both in the unreinforced alloy and in the composites. But the transition loads for the composites were much higher than that of the alloy. The transition loads increase with the increase in content of tungsten carbide, but decreases with increase in sliding speeds. The above discussed composites are possible candidate materials for bearing sleeves, piston and cylinder liner, and aircraft brakes applications.

Synthesis of complex carbonitrides Ti1−x WxC1−y Ny

We have studied the effect of process factors (temperature, nitrogen pressure, composition) on synthesis of carbonitrides Ti1−xWxC1−yNy from the starting components (WC, TiC, TiN) with particle size 10–12 μm. Under realistic conditions, we have determined the range of existence for homogeneous cubic carbonitrides. As the tungsten carbide content increases, the temperature needed for synthesis of homogeneous carbonitrides increases. Synthesis of complex carbonitrides occurs in two steps: via formation of titanium carbonitride followed by dissolution of WC in the latter, and by formation of the complex titanium-tungsten carbonitride. We have established that the major reason for the appearance of the W2C phase is thermal dissociation of titanium nitride.