Zirconium Carbide Research Articles

2MeV He ion irradiation of zirconium carbide coatings: Effects of substrate type

This study sought to investigate the effect of substrate type on the radiation resistance of zirconium carbide (ZrC) coatings as a candidate for plasma facing materials. The first step involved growing ZrC coatings on tungsten carbide (WC) and glass substrates using homemade DC Magnetron Sputtering. The different ZrC coated substrates were then irradiated with 2 MeV He ions to a fluence of 7×1015 ions/cm2 using a 3 MV Van de Graaff accelerator. The surface morphologies of the coatings were examined before and after irradiation by Field Emission Scanning Electron Microscopy (FESEM). Additionally, X-Ray Diffraction and Raman spectroscopy were used to evaluate the microstructure evolution of the coatings. Displacement damage and He ion concentration in the coatings were evaluated by SRIM simulation. A comparison of different substrate types coated with ZrC revealed that ZrC coating on tungsten carbide substrates have higher irradiation resistance than ZrC coating on glass substrates.

Reduced He ion irradiation damage in ZrC-based high-entropy ceramics

Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety. The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials, which has been proven in alloys. However, whether or not high entropy can also improve the irradiation resistance of ceramics, especially the mechanism therein still needs to be uncovered. In this work, the irradiation and helium (He) behaviors of zirconium carbide (ZrC)-based high-entropy ceramics (HECs), i.e., (Zr_0.2Ti_0.2Nb_0.2Ta_0.2W_0.2)C, were investigated and compared with those of ZrC under 540 keV He ion irradiation with a dose of 1×10¹⁷ cm⁻² at room temperature and subsequent annealing. Both ZrC and (Zr_0.2Ti_0.2Nb_0.2Ta_0.2W_0.2)C maintain lattice integrity after irradiation, while the irradiation-induced lattice expansion is smaller in (Zr_0.2Ti_0.2Nb_0.2Ta_0.2W_0.2)C (0.78%) with highly thermodynamic stability than that in ZrC (0.91%). After annealing at 800 ℃, ZrC exhibits the residual 0.20% lattice expansion, while (Zr_0.2Ti_0.2Nb_0.2Ta_0.2W_0.2)C shows only 0.10%. Full recovery of the lattice parameter (<i>a</i>) is achieved for both ceramics after annealing at 1500 ℃. In addition, the high entropy in the meantime brings about the favorable structural evolution phenomena including smaller He bubbles that are evenly distributed without abnormal coarsening or aggregation, segregation, and shorter and sparser dislocation. The excellent irradiation resistance is related to the high-entropy-induced phase stability, sluggish diffusion of defects, and stress dispersion along with the production of vacancies by valence compensation. The present study indicates a high potential of high-entropy carbides in irradiation resistance applications.

Fabrication and Photothermal Phase Change Properties of Polyethylene Glycol/Melamine Sponge/Polyurethane/Zirconium Carbide Composites

ABSTRACT Solar energy is a green, sustainable, and abundant renewable resource. Adding photothermal conversion materials to phase change materials can increase the photothermal conversion efficiency and heat storage capacity of phase change materials. In this work, polyethylene glycol (PEG) was used as phase change material, zirconium carbide was used as photothermal conversion material, melamine sponge was used as the carrier, and polyurethane was used as coating to prepare phase change photothermal composites. The effects of PEG concentration and zirconium carbide concentration on the thermal properties of composite phase change materials were discussed. The results showed that when the PEG concentration was 80% and the zirconium carbide concentration was 5%, the composites showed better comprehensive properties with less leakage and high enthalpy (186.5J/g). Surface temperature of the composites could rise to 54°C in 300 s under infrared light, and the enthalpy value of phase change and the photothermal conversion capacity could maintain 97% after 50 cycles of testing. The composites could be used in various fields such as car seats, cushions, and mattresses.

Synthesis and study of dense materials in the Zr–Al–C system

The initial powders Zr, Al, C and Zr, Al, Sc were used for the synthesis of MAX phases of the composition Zr2AlC and Zr3AlC2. The highest content (50.4 vol%) of the MAX phase Zr3AlC2 was obtained using the initial powders Zr/Al/Zr in the ratio of components 1:1.5:2 with the addition of 5 vol% Al. The optimal temperature for the synthesis of a material based on the MAX phase Zr2AlC is 1525° C, a material based on Zr3AlC2 is 1575°C. The structure of the synthesized MAX materials obtained includes elongated grains of the composition Zr2AlC and Zr3AlC2, which determines their high strength. Zirconium carbide, as an intermediate phase, is always present in the final products. Due to the large evaporation of aluminum, the ZrO2 phase is also present in the synthesis products. Excess aluminum contributes to the greatest formation of Zr2AlC and Zr3AlC2 phases during synthesis.

Applying the Taguchi to Optimization the densification, and flexural strength of ZrB2–SiC–ZrC-CNFs

The purpose of this research is to optimize the densification, microstructure and flexural strength of ZrB2-25 vol% SiC composites reinforced by carbon nano fibers (CNFs) and zirconium carbide (ZrC). Spark Plasma Sintering (SPS) was applied for composites consolidation. Taguchi orthogonal array L9 as the design of statistical experiments (DOE) was evaluated to optimize the additives, as well as SPS parameters (temperature and time). Three levels were defined for each factor. The relative density (R.D%) and flexural strength of the samples were calculated based on Archimedes' law and the three-point bending test. Moreover, analysis of variance (ANOVA) was utilized to determine the importance of effective parameters and to optimize the SPS variables and compounds (the amount of CNFs and ZrC). The microscopic structure of surfaces was examined through field emission scanning electron microscopy equipped with energy dispersive spectroscopy (FE-SEM, EDS). The results showed that the best output of relative density and flexural strength was equal to 99.8% and 610 MPa, respectively, with an average ZrB2 grain size of 9.6 μm in a composite containing 15 vol% CNFs and 10 vol% ZrC and SPSed at 1875 °C for 7 min.

Machine learned interatomic potential for dispersion strengthened plasma facing components.

Tungsten (W) is a material of choice for the divertor material due to its high melting temperature, thermal conductivity, and sputtering threshold. However, W has a very high brittle-to-ductile transition temperature, and at fusion reactor temperatures (≥1000K), it may undergo recrystallization and grain growth. Dispersion-strengthening W with zirconium carbide (ZrC) can improve ductility and limit grain growth, but much of the effects of the dispersoids on microstructural evolution and thermomechanical properties at high temperatures are still unknown. We present a machine learned Spectral Neighbor Analysis Potential for W-ZrC that can now be used to study these materials. In order to construct a potential suitable for large-scale atomistic simulations at fusion reactor temperatures, it is necessary to train on ab initio data generated for a diverse set of structures, chemical environments, and temperatures. Further accuracy and stability tests of the potential were achieved using objective functions for both material properties and high temperature stability. Validation of lattice parameters, surface energies, bulk moduli, and thermal expansion is confirmed on the optimized potential. Tensile tests of W/ZrC bicrystals show that although the W(110)-ZrC(111) C-terminated bicrystal has the highest ultimate tensile strength (UTS) at room temperature, observed strength decreases with increasing temperature. At 2500K, the terminating C layer diffuses into the W, resulting in a weaker W-Zr interface. Meanwhile, the W(110)-ZrC(111) Zr-terminated bicrystal has the highest UTS at 2500K.

Assimilation of Nanoparticles of SiC, ZrC, and WC with Polyaryletherketone for Performance Augmentation of Adhesives

The present paper reports the analyses of results obtained from experiments carried out to explore the challenge of homogeneous, uniform, and deagglomerated dispersion of ultra-heavy nanoparticles (NPs) in the high-performance polyaryletherketone (PAEK) matrix. An equal and fixed amount of (0.5 vol. %) NPs of silicon carbide (SiC), zirconium carbide (ZrC), and tungsten carbide (WC) were dispersed in a PAEK matrix and compression molded to develop three different nanocomposites. Simultaneously, nano-adhesives of the same composition were also developed to join the stainless steel adherends. The composites and adhesives were characterized for their physical, thermal, thermo-mechanical, thermal conductivity (TC), and lap shear strength (LSS) behavior. It was observed that SiC NPs performed significantly better than ZrC and WC NCs in all performance properties (LSS: 154%, TC: 263%, tensile strength: 21%). Thermal conductivity (TC) and tensile properties were validated using various predictive models, such as the rule of mixture parallel model, the Chiew and Glandt model, and the Lewis model. Scanning electron micrographs were used for the morphological analysis of LSS samples to detect macro- and micro-failure. Micrographs showed evidence of micro-striation and plastic deformation as a micromodel, as well as mixed failure, i.e., adhesive-cohesive as a macro-failure mode.

Effect of nonstoichiometry on anisotropy of elastic properties of disordered cubic zirconium carbide ZrCy

The elastic constants c11, c12, c44 are determined for the first time as functions of the carbon content y in the homogeneity region ZrC0.60 - ZrC1.00 of nonstoichiometric disordered cubic ZrCy zirconium carbide. It is established that the elastic stiffness constants cij of disordered ZrCy carbide decrease with an increase in the defectiveness of the carbon sublattice of zirconium carbide. An increase in the deviation of the ZrCy composition from stoichiometry leads to a slight decrease in the anisotropy of the elastic properties. The elastic properties of zirconium carbide are anisotropic, since they change depending on the crystallographic direction [hkl] due to differences in the arrangement of atoms and interatomic bonds in various directions. It is found that the values of elastic moduli depend on the crystallographic direction [hkl], and the maximum and minimum the Young's moduli are observed in the [001], [010], [100] or [±1 ± 1 ± 1] directions of cubic ZrCy carbide, respectively. Small changes in the elastic characteristics of ZrCy depending on the [hkl] direction indicate a weak elastic anisotropy of cubic zirconium carbide. It is shown that the calculated Vickers hardness and Debye temperature of polycrystalline disordered cubic ZrCy carbide increase non-linearly with increasing relative carbon content y.

A Prominent Iron Silicides Strewn Field and Its Relation to the Bronze Age/Iron Age Chiemgau Meteorite Impact Event (Germany)

About 20 years ago, amateur archeologists and local history researchers discovered the iron silicide (FESI) strewn field measuring about 60 km x 30 km in the districts of the Chiemgau and the Inn-Salzach region in southeast Germany. They evidenced the connection between the FESi distribution and the pervasive rim wall craters and suggested a meteorite impact event, now widely recognized under the name of the Chiemgau impact. Widespread in the strewn field and in individual finds far beyond it they recovered and documented thousands of FESI particles of millimeter to centimeter size with a total mass of more than 2 kg, whereby a large lump of 8 kg stands out as a single find. The find layer is largely uniformly located at a depth of 30 - 40 cm in a glacial loose sediment soil. Microprobe, SEM-EDS, TEM and EBSD analyses determined as main minerals gupeiite and xifengite, subordinately hapkeite, naquite and linzhite. Besides the main elements Fe and Si of the matrix, more than 30 other chemical elements have been addressed so far, including uranium and various REE. Incorporated into the FESI matrix are the carbide minerals moissanite and titanium carbide as superpure crystals, and khamrabaevite, zirconium carbide, and uranium carbide, furthermore CAIs. SEM images indicate shock metamorphism. The present article describes the discovery history of this worldwide unique FESI occurrence with the exact find situations, as well as the very varied morphologies of the find particles with the macroscopically recognizable components and SEM EDS examples.

Densification mechanism, microstructure and mechanical properties of ZrC ceramics prepared by high-pressure spark plasma sintering

The traditional way of densifying high-melting-point ceramics at high temperatures with long soaking time leads to severe grain coarsening, which degrades the mechanical properties of ceramics. Here, highly dense (∼98%) zirconium carbide (ZrC) ceramics with limited grain growth were obtained by spark plasma sintering (SPS) at relatively low temperatures, 1900 ℃, with a high pressure up to 200 MPa in a reliable carbon-fiber-reinforced carbon composite (Cf/C) mold. Subgrains and high-density dislocations formed in the high-pressure sintered ceramics. The hardness and fracture toughness of the prepared highly dense ZrC ceramics reached 20.53 GPa and 2.70 MPa·m1/2, respectively. The densification mechanism was mainly plastic deformation under high pressure. In addition, ZrC ceramics sintered at high pressure possessed a high dislocation density of 7.30 × 1012 m−2, which was suggested to contribute to the high hardness.

Preparation of ZrC embedded carbon rods via thermal decomposition of metal organic frameworks

Synthesis of uniform, spherical ZrC is difficult and generally not cost-effective, as is the case for most ultra-high temperature ceramics. High aspect ratio particles for reinforcement of ceramic composites are even more difficult to synthesize. Metal organic frameworks (MOF) are crystalline coordination polymers composed of multidentate organic linkers bridging metal nodes to form porous structures. Thermal decomposition of MOFs presents a new and cost-effective route to synthesis of ZrC. In this study, heat treatment at 2000 °C of MOF PCN-222 produces zirconium carbide (ZrC) within a highly anisotropic particle. The resulting rod-shaped, glass-like carbon matrix embedded with ZrC crystals is described. These rods have potential as reinforcements for high temperature applications and as a synthetic route for ultra-high temperature ceramics with unique morphologies.

Lightning strike damage behavior of zirconium carbide and copper modified short-carbon-fiber-reinforced boron phenolic resin composites under 200 kA

By using artificial lightning of standardized Waveform A, this study explored the lightning strike protection (LSP) effect of zirconium carbide (ZrC) and copper (Cu) modified short-carbon-fiber-reinforced boron phenolic resin composites under a current peak of 200 kA. Based on the results of visual observation, micro-morphologies characterization, three-dimensional shapes and X-ray detection, we observed a remarkable LSP effect in this composite, which can be attributed to the high bending strength of the laminated structure, and the well thermal resistance of ZrC. Meanwhile, the addition of Cu powders with concentrations of 10% was demonstrated to enable efficiently withstand the lightning strike and prevent crack propagation since the electrically conductive path. Our findings proposed a promising LSP skin material for the aircraft, which will maintain structural stability under the impact of a lightning strike.

Influence of Quantum Oscillations in the Thermal Scattering Law of Zirconium Carbide on Neutron Thermalization and Criticality

Zirconium carbide (ZrC) is a candidate material for advanced high temperature reactors, including space nuclear thermal propulsion applications. Thermal scattering laws (TSLs) are generated in the incoherent approximation for carbon bound in ZrC [C(ZrC)] and zirconium bound in ZrC [Zr(ZrC)], using ab initio lattice dynamics methods. Disordered alloy theory is introduced to improve treatment of isotopic composition within the elastic scattering cross section. Localized higher-energy vibrational modes and the presence of a phonon band gap in C(ZrC) cause quantized oscillation in the TSL atypical of nonhydrogenous solids. These oscillations yield a significant likelihood of large energy downscattering and upscattering interactions such that the quanta of energy transfer affecting neutron thermalization is substantially greater than classically expected. MC21 critical mass calculations of ZrC mixtures with high-enriched uranium demonstrate an impact of TSLs when compared to a free-gas treatment for thermal neutron–driven 235U loadings. The critical mass of homogenous mixed moderator systems of ZrC and reactor-grade graphite are also sensitive to the ZrC TSL. Moreover, the effect of quantized energy exchange on the neutron spectra is found to influence the temperature feedback coefficient.

Testing of ITER diagnostic pressure gauges in preparation of final design review

Hot cathode ionization gauges will measure neutral gas pressures in the vacuum vessel of ITER. Overall 52 gauge heads are distributed in the divertor, the equatorial ports and pumping ducts. Present design and prototype testing of diagnostic pressure gauge (DPG) heads is presented. Focus is on the development of a novel type of cathode, which is able to overcome major issues that emerged during the preliminary design phase. In comparison with the formerly employed yttria coated tungsten–rhenium filament, the operational stability of the present cathode, which uses an indirectly heated plate of zirconium carbide as the electron emitter, is enhanced in terms of needed heating current and accuracy. A major issue of filament deflection by electromagnetic forces was overcome through the rigid setup, which still allows for the compensation of differential thermal expansion and provides a high reproducibility in manufacturing. Reliable functioning for long periods was proven successfully in a superconducting magnet, covering the required pressure range. Prototype testing revealed an issue during permanent operation in hydrogen at high pressures: erosion can lead to limited life-time of the cathode. The introduction of interlayer foils can retard but not completely inhibit the process. A possible mechanism based on reaction and diffusion of carbon is proposed.

A first-principles study of the electronic, mechanical, vibrational, and optical properties of the zirconium carbide under high pressure

Zirconium carbide is a compound widely used in cutting tools, nuclear reactors, field emitter arrays and solar energy receivers; additionally, combined with other materials, it can be used in rocket technology and the aerospace industry. For this work was studied the effect of the high hydrostatic pressure on the electronic, mechanical, vibrational, and optical properties of the ZrC, from first principles calculations based on the Density Functional Theory. The calculated enthalpy and cohesive energy data show a B1 (NaCl) to B2 (CsCl) phase transition at 297 GPa. For the B1 phase, results for the calculated equilibrium lattice parameters, bands structure, electron and phonon densities of states, elastic moduli constants, entropy, enthalpy, Gibbs free energy, heat capacity, reflectivity, loss function, conductivity, and dielectric function are consistent with the available experimental and theoretical data. Our results for phonons show that the B1 phase is dynamically stable; in contrast, the B2 phase is not stable. Furthermore, when pressure is applied, the calculated density of electronic states shows that the C 2p-orbitals around the Fermi energy contribute significantly to the conduction band, turning the compound into a ductile the material, with a mixture of metallic and ionic-covalent bonds. On the other hand, the study of the mechanical properties of the B1 phase shows a highest mechanical resistance and maximum thermal absorption, above 356 K and 638 K, respectively; but these switch to higher temperatures as pressure is applied. Finally, the B1 phase of the ZrC is a good coating material and a photon detector at low frequencies in the UV region, but also at the visible and infrared regions; although, increasing the pressure, the values of the optical properties increase. The increase of the parameters’ values of the studied properties, as the pressure increases, indicates that the ZrC could be more efficient in a wider range of applications.

Grain size dependence of thermally induced oxidation in zirconium carbide

Grain size dependence of thermally induced oxidation in zirconium carbide

Nonlinear Absorption Response of Zirconium Carbide Films.

Zirconium carbide (ZrC), a novel representative of the MXene family, has attracted considerable interest because of its outstanding physicochemical properties and potential applications in optoelectronic devices. For improving its performance as an optical modulator for ultrashort lasers, there is a call to continue studying the nonlinear optical behavior of MXene ZrC. Herein, for the first time, MXene ZrC films were fabricated on fused silica by magnetron sputtering deposition technology and used as a saturable absorber (SA) optical modulator in a passive Q-switched Nd:YAG laser. The saturation absorption behaviors of the prepared ZrC films were characterized by the Z-scan method. Their morphology, band structure, damage threshold, carrier recovery time, and saturation absorption properties were analyzed. The experimental results show that the MXene ZrC SA films exhibit excellent nonlinear optical characteristics, with a saturation intensity of 48.4 MW/cm2, a large modulation depth of 6.9%, and an ultrashort recovery time of 2.72 ps. In addition, the damage threshold of MXene ZrC SA films was estimated to be greater than 0.2516 J/cm2. By integrating the ZrC SA film optical modulator into the oscillator of the Nd:YAG laser, we achieved stable operation of the Q-switched laser with a central wavelength at 1.06 μm, with the shortest pulse width of 78 ns. The results of this study demonstrate the potential use of MXene ZrC SA films as optical modulators in ultrashort lasers.

Influence of coatings based on Zr and Ti on the wear resistance of cemented carbide tools when turning transport machines’ parts from structural steels

The influence of coatings based on titanium carbide and zirconium carbide, obtained by PVD method, on cutting tool wear resistance under conditions of the longitudinal turning of transport machines’ parts of steel 45 and stainless steel 12H18N10T by inserts of hard alloy grade T15K6 was investigated. It has been experimentally established that the presence and composition of the coating on the working surfaces of the tool in most cases contributes to a significant reduction in the intensity of wear of cemented carbide inserts. When turning stainless steel 12H18N10T, the best result was demonstrated by the coating ZrN + (Ti–Zr) N + TiN, which provided not only the minimum intensity of wear, but also the expansion of the range of optimal cutting speeds. When machining structural steel 45, the maximum reduction in the wear intensity of the cutting inserts was observed with the use of a single-layer TiN coating and a (Ti,Zr)N coating.

Deposition of biomimetic biocompatible oxides on metallic glass surface by electro‐discharge coating process

AbstractBulk metallic glass demonstrates superior mechanical properties and excellent bio‐mechanical stability compared to routinely used biomaterials like titanium, cobalt‐chromium, stainless steel, et cetera. However, the metallic glass surface do not easily adhere to the leaving tissues due to native bio‐inert oxide layer, which have poor wear resistance and low hardness. In this current study an innovative method for surface coating of bulk metallic glass by mixing hydroxyapatite powder during electro‐discharge machining has been employed. A biomimetic nano‐porous bio‐ceramic layer of oxides and carbides was deposited on metallic glass surface. The modified surface integrity and composition were investigated by scanning electron microscopy, energy‐dispersive x‐ray spectroscopy, and x‐ray diffraction characterization techniques. The characterization results confirmed the formation of a natural bone‐like nano‐porous surface topography on the metallic glass surface using a novel hydroxyapatite‐mixed electro‐discharge coating process. In addition, a favourable surface chemistry in the form of bioceramic carbides (zirconium carbide, titanium carbide) and zirconium oxide layers, was achieved.

Preparation of ZrC coating in TRISO fuel particles by precise transportation of solid precursor and its microstructure evolution

Very-high-temperature gas-cooled reactors (VHTRs) with outlet temperatures above 1273 K show higher thermal efficiencies, which require fuel elements to operate at higher temperatures. In such situations, the conventional silicon carbide (SiC) coatings in TRISO particles might not be able to adapt to such high temperatures, and zirconium carbide (ZrC) can function as a potential fission product barrier material. For ZrC coating, controlling the stoichiometric ratio is a key challenge in the preparation process in fluidized bed. In this paper, a novel solid precursor feeding mode was proposed, combining quantitative powder feeding with cold transport. By controlling the powder feeding rate of ZrCl4 and the flow rate of propylene, the C/Zr atomic ratio in ZrC coating was controlled accurately. ZrC coatings with different stoichiometric ratios were successfully prepared via fluidized-bed chemical vapor deposition (FB-CVD). The ZrC coatings were subjected to high temperature heat treatment for different times from 2473 to 2673 K under argon atmosphere and the microstructure and property evolutions after high-temperature heat treatment were investigated. The deposition mechanism of ZrC coating was proposed.