Spark Plasma Sintering Technique Research Articles

Medium heavy alloy fabrication with ultrafine grain and high performance via spark plasma sintering

• Medium heavy alloys were successfully fabricated for the first time using the spark plasma sintering technique. • Nearest theoretical density achieved for the Ni-37W-5Co alloy. • Σ3 boundaries are formed in the Ni matrix. • The Ni-37W-5Co alloy has the highest UTS of 740 MPa. W-Ni-Co, W-Ni-Co-Ta, and W-Ni-Co-B 4 C medium-heavy alloys and alloy composites are developed using the spark plasma sintering technique in the current study. This work aims to investigate the structure–property correlations of the three different compositions mentioned above. The compacts are subjected to extensive metallurgical and mechanical testing. Annealing twins are formed in the Ni matrix phase, and the density of the twins revealed a difference in material strength. The densification response and tensile tests showed that the base alloy W-Ni-Co has the highest tensile strength (740 MPa), an elongation of 4.5%, and a relative sintered density of 96%.

Microstructure-driven excellent energy storage NaNbO3-based lead-free ceramics

Alkali niobate-based energy storage ceramics have recently drawn considerable attention because of their ultrahigh recoverable energy storage density (W rec ) and environment-friendly feature. However, it is still quite challenging for them to maintain a high energy storage efficiency (η). Herein, spark plasma sintering (SPS) technique was adopted to tailor the microstructure of Na 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O 3 lead-free ceramics. Compared with their conventional sintered counterparts, the samples sintered by SPS exhibit more homogeneous microstructure, finer grains, decreased porosity and fewer oxygen vacancies. Consequently, a high breakdown strength, small remanent polarization and low polarization hysteresis give rise to excellent comprehensive energy storage performance (W rec = 6.68 J/cm 3 , η = 90.5%) of the SPS sintered ceramics. This work not only provides a potential lead-free energy storage ceramic system, but also reveals the remarkable role of the tailored microstructure in improving energy storage properties.

High-performance titanium-based composite strengthened with heterogeneous network structure

By adjusting the particle size of Ti6Al4V(TC4) powders and the distribution of boron particles, a high-performance heterogeneous network structure titanium matrix composites were fabricated through the spark plasma sintering (SPS) technique. In the present work, TiB whisker (TiBw) are in situ synthesized around the boundaries of the small size TC4 (STC4) particles, and formed into a TiBw network structure. The STC4 particles of the network surround the larger size TC4 (LTC4) particles to form a new heterogeneous network structure similar to the shape of a sunflower. The heterogeneous network structure consisted of coarse grain zones (LTC4) and fine grain zones (TiB/STC4) is formed in the microstructure. In light of tensile results, the tensile strength and ductility of TiB/TC4 composites with heterogeneous network structure are about 987.5 MPa and 11.5 %, respectively, which are 16.6 % and 35.3 % higher than those of TC4 alloy. The improvement of mechanical properties is mainly due to the interface strengthening mechanism of heterogeneous network structure and the hindrance and pinning mechanism of reinforcements to dislocation movement. The improvement of ductility depends on the inhibition of crack propagation by the heterogeneous network structure and the existence of high ductility coarse grain zone.

Dependence of residual thermal stress in cermets on the sintering technique

The effects of representative sintering techniques on the residual thermal stress (RTS) in the as-prepared cermets were investigated using the WC-Co composites as an example. The real processing parameters of the spark plasma sintering (SPS) and sinter-hot isostatic pressing (Sinter-HIP) techniques were introduced to quantify RTS and its mechanisms. The real microstructures of cermets were used in the models for evaluation of RTS distributions in different phases. The macro-mesoscale coupled calculations indicated that during the cooling of both the SPS and Sinter-HIP processes, the WC phase of the sintered cermets has a state of compressive stress, while Co phase has a tensile stress state. The internal stress magnitude of both phases increases linearly with the decrease of temperature. There are larger temperature and displacement fields in the SPSed cermets compared to those prepared by Sinter-HIP. The stress accumulation in the SPS process is faster than that in the Sinter-HIP by 30%. The RTS in the SPSed cermets is highly concentrated at the acute dihedral angles of WC/Co interfaces, which tends to promote the face-centred cubic (fcc) to hexagonal close-packed (hcp) martensitic transformation of the Co phase.

Forming and heat resistance study of NiAl‒ZrO<sub>2</sub> gradient thermal barrier material for superalloys

In this work the spark plasma sintering (SPS) technique was used to forming a functionally gradient thermal barrier material based on nickel aluminide (VKNA) and zirconium oxide (YSZ). Layer-by-layer powders of VKNA / mixtures VKNA + 15 (30) % YSZ / YSZ were consolidated in a graphite matrix at 1070°C in a vacuum atmosphere for 5 minutes and at a pressure of 30 MPa. It is determined that the sintered material has good adhesion of layers, there are no interlayer boundaries. To check the functionality of the material, thermocyclic tests were carried out at 1100°C in the air. The results showed that the material containing the sublayer VKNA + 30 % YSZ has better heat resistance. Ill. 5. Ref. 28. Tab. 2.

Microstructure and mechanical properties of mechanically-alloyed CoCrFeNi high-entropy alloys using low ball-to-powder ratio

High-entropy alloys are extensively studied due to their very promising properties. However manufacturing methods currently used to prepare HEAs are complicated, costly, and likely non-industrially scalable processes. This limits their evolution and poses questions regarding the material's applicability in the future. Considering the abovementioned point, we developed a novel methodology for efficient HEA production using a low ball-to-powder ratio (BPR). Using different milling times, we manufactured four HEA powder precursors using a BPR of 5:1, which were later sintered via the Spark Plasma Sintering technique and heat treated. Microstructural characterisation was performed by optical microscopy, Scanning Electron Microscopy equipped with EDS and EBSD detectors, and X-ray diffraction. Mechanical properties were measured using nano and microhardness techniques. In this work, we follow the structural evolution of the material and connect it with the strengthening effect as a function of milling time. Furthermore, we discuss the impact of different sintering and annealing conditions, proving that HEAs characterised by high mechanical properties may be manufactured using low BPR.

Effect of Ta addition on the sinterability of spark plasma sintered W-Ni-Fe alloy

The purpose of this research is to investigate and characterize the W-Ni-Fe-Ta compositions by solid-state sintering using the Spark Plasma Sintering (SPS) technique at a relatively lower temperature. The sinterability of W-Ni-Fe ternary tungsten heavy alloy (WHA) with the addition of Tantalum in predetermined compositions was sintered using SPS at 1100°C under 30 MPa pressure. The effect of Ta addition on WHA densification, microstructure, and mechanical properties was studied. Ni was found to act as an activator in the sintering of tungsten. SEM and energy dispersive spectroscopy revealed an even distribution of Ta in the W and Ni-Fe matrix. The data of hardness and ultimate tensile strength were explained using grain size, contiguity, and the formation of brittle intermetallic phases. W-7Ni-3Fe-5Ta alloy composition has the highest ultimate tensile strength of 870 MPa, 189.2 HV0.5kgf hardness, and 83.42% relative sintered density. During the tensile test, W grain cleavage fracture, W-W decohesion, matrix tearing, and W matrix intergranular types of fracture surface were observed.

Effects of Bi Alloying on the Thermoelectric Properties of p‐Type Mg3Sb2‐xBix Solid Solutions

AbstractBismuth is the most common alloying element for high‐performance Mg3Sb2‐based thermoelectric compounds. However, the electrical and thermal transport data is lacking for undoped Mg3(Sb, Bi)2 solid solutions. In this study, theoretical calculation results show that Bi alloying can reduce the band gap of Mg3Sb2, favoring the regulation of carrier concentration. Both Mg3Sb2 and Mg3SbBi compounds present a single band structure on the valence band maximum at Γ of the Brillouin zone. Incorporating the Bi element can slightly increase the density of states (DOS) on the valence band maximum, which is beneficial for the Seebeck coefficient. Mg3Sb2‐xBix (0≤x≤0.8) compounds were experimentally prepared via ball milling (BM) combined with the spark plasma sintering (SPS) technique. The carrier concentration, electrical conductivity, and power factor of the samples tend to increase with the increasing Bi content. Bismuth alloying significantly reduces the total thermal conductivity in the low‐temperature range, with the lowest value of 0.65 Wm−1K−1 obtained at ∼400 K for the x=0.2 sample. The peak ZT value of 0.077 at 800 K and the average ZT of 0.051 in the temperature range of 450–800 K are obtained for the x=0.2 sample, which is 93% and 219% higher than those of the unalloyed sample, respectively. This work reveals the Bi‐alloying induced transport mechanism and provides fundamental thermoelectric data regarding the undoped Mg3Sb2‐xBix (0≤x≤0.8) solid solutions.

Tribological and Mechanical Characteristics of Mg–Zn6.0–Y1.2–Zr0.2 alloy by SPS Technique: Natural and Agro-Waste Utilization

In India, urban solid waste generation has risen over the last decade. The aspect of waste generation is a large amount of waste materials among all solid waste types. While using ash particles eliminates waste, it also contributes desirable qualities. In this research work, the effects of Himalayan nettle leaf ash (HNLA) and bean pod ash (BPA) with molybdenum trioxide (MoO3) on the ZWK611 (Mg–Zn6.0–Y1.2–Zr0.2) alloy is examined. The as-cast alloy exhibits an α-Mg matrix, and cubic γ-phases are formed in addition to MoO3 particles. In this work, an attempt was made to choose a ZWK611 alloy reinforced with HNLA and BPA by varying weight percentages (X = 4, 8, 12, and 15%) with a constant weight percentage of MoO3 (5%) fabricated using spark plasma sintering (SPS) technique. The mechanical and physical properties were tested for both as-cast alloy and magnesium hybrid composites. Surface morphology and XRD are analysed to identify material behaviour. The addition of 12% (HNLA-BPA)/5%(MoO3) hybrid composite exhibits high strength as compared to the as-cast alloy.

Mechanical behavior of ion-irradiated ODS RAF steels strengthened with different types of refractory oxides

One of the most promising candidates for constructing IV generation nuclear reactors is Oxide Dispersed Strengthening (ODS) Reduced Activation Ferritic (RAF) steel. It is known that introducing refractory oxides to the ferritic matrix makes it possible to obtain a brand-new kind of materials with an excellent set of properties. In the present work, the authors focused on verifying materials' structural and mechanical properties strengthened by three different types of refractory oxides submitted to ion-irradiation. Three materials with an elemental chemical composition of 12 %Cr, 2 %W, 0.3 %Ti, and strengthened with 0.3% Y2O3 or Al2O3 or ZrO2 were produced by mechanical alloying and subsequently consolidated by Spark Plasma Sintering technique. Manufactured materials have been submitted to high energy (500 keV) Ar-ion irradiation at room temperature with three fluences (up to 5x1015 ions/cm2). This procedure allowed to generate a thin, strongly damaged zone with approximate thickness of 230 nm. SEM/EBSD and TEM bservations, Grazing Incidence X-ray Diffraction analysis, and nanoindentation tests have been included in examination of modified layers. Implementation of these techniques allowed to reveal alteration of structural and mechanical features between unmodified material and radiation-affected layer. Obtained results showed a strong correlation between the strengthening oxide and materials' microstructural and mechanical behavior under radiation damage. It has been proved that below 1x1015 ions/cm2 mechanical properties in the modified layer of all materials are very similar. Reported behavior may be related to the efficient annealing of the radiation defect process. Above this limit, significant differences between the materials are visible. It is believed that described phenomenon is directly related to the presence of the structural features and their capacity to act as defect sinks. Consequently, type of dominant mechanisms occurring in modified layer is proposed.

Investigation of microstructure, mechanical properties, and wear behavior of aluminum A380 nanocomposite reinforced with graphene nanosheets produced by spark plasma sintering technique

The study reports the development of graphene nanosheets reinforced aluminum A380 matrix nanocomposites using powder metallurgy. Nanocomposites are fabricated by a mechanical alloying process and the bulk nanocomposites are prepared by spark plasma sintering (SPS) technique in a vacuum at 540 °C. 0.25 wt%, 0.5 wt%, 0.75 wt%, and 1 wt% of graphene nanosheets are used as a refinement for nanocomposites. Microstructural, mechanical properties, and wear behavior of the Al A380–graphene nanocomposites were investigated. Testing and analysis of fabricated composites revealed an improvement in hardness (59.96%) and wear rate (108.57%). Grain refinement action caused by graphene, high hardness, and graphene's self-lubricating nature is reasoned for these improvements. Optical microscopy and scanning electron microscopy (SEM) analysis were used to investigate microstructures of the nanoparticle distribution in the nanocomposites of the SPS samples. The wear resistance of resultant composites is reported at a higher side, decreasing friction coefficient owing to graphene's self-lubricating nature. Moreover, the incorporation of lubricant graphene nanosheets significantly reduced the wear rate and the friction coefficient in comparison with the Al A380 matrix composites. Wear morphology is characterized using SEM. In the end, the Al A380–0.5% graphene nanocomposite sample represents the greatest hardness and wear behavior, and good microstructure to compare with the other experimented samples.

Synthesis of Mg‐stabilized nitrogen‐rich alpha‐sialons along Si3N4–0.5Mg3N2:3AlN line via field‐assisted sintering

AbstractThe present study reports for the first time the synthesis and evaluation of magnesium (Mg)‐doped nitrogen‐rich (N‐rich) sialon ceramics exploring the possible existence of Mg‐stabilized single‐phase alpha‐sialon (on the Mg‐alpha‐sialon plane). Mg‐stabilized N‐rich sialons, with the general formula of MgxSi12−2xAl2xN16 having x value in the range of 0.2–2.2 for the composition laying along the Si3N4–0.5Mg3N2:3AlN line, were synthesized at 1500°C, using nano‐size starting powder precursors and field‐assisted (or spark plasma) sintering technique. Consolidated sialon ceramic samples were characterized for their microstructure, phase stability regime, and physical and mechanical properties. Although a relatively low synthesis temperature was adopted, well densified sialon samples were achieved; however, the densification of the samples became difficult with a higher x value (containing high Mg3N2/AlN content). Contrary to what was expected to take place, a single‐phase Mg‐doped sialon was not obtained near the N‐rich line (on Mg‐alpha‐sialon plane). Such distinctive behavior in Mg‐doped sialons was supposed to be due to the formation of a highly stable Mg‐containing aluminum nitride polytype phase, which consumed most of the high‐temperature transient liquid phase. Mg‐doped N‐rich sialon sample having the maximum amount of alpha phase depicted a remarkable hardness (HV10) of 21.4 GPa and a fracture toughness of 3.5 MPa m1/2.

Influence of sintering time on diffusion bonding of WC-10Co and AISI4340 by spark plasma sintering

It is challenging to obtain successful bonding between cemented tungsten carbide and steel due to the large differences in their physical and mechanical properties. We used spark plasma sintering (SPS) technique and successfully bonded WC-10Co and AISI4340 high-strength steel at a low temperature. The effects of sintering time (5–20 min with a gap of 5 min) on their diffusion bonding were examined. The microstructure of the bonded composite materials was evaluated, and formed phases were identified. The mechanical properties were investigated, and the importance of processing parameters of SPS was discussed. The results show a crack-free continuous metallurgical bonding achieved at 1000°C, and the bonding strength increased with increasing holding times of 5, 10, 15, and 20 min. The sintered WC-10Co powders obtained nearly full density (99.07%) with an average maximum hardness of 1763 HV5. A special arrangement was used to determine the tensile bonding-strength with maximum average of 152 MPa at 20 min.

Microstructure and corrosion resistance of powder metallurgical Ti-Nb-Zr-Mg alloys with low modulus for biomedical application

Due to their bioinert nature, titanium alloys show poor bone-implant integration and insufficient osseointegration in vivo. In this study, a series of low elastic modulus bioactive titanium alloys with a nominal composition of Ti-13Nb-13Zr-1.25 Mg (wt%) were prepared using mechanical alloying and spark plasma sintering techniques. The microstructures, mechanical properties, degradation behaviors and in vitro bioactivities of these alloys were systematically investigated. After sintering at 700 °C, the α-Ti, β-Ti and Nb (Zr)-rich phases were present, and the Mg was uniformly distributed. In addition to above-mentioned phases, the α″ phase was found after sintering at 800 °C or 900 °C. The density, elastic modulus, yield strength, ultimate compressive strength and corrosion resistance all increased with increasing sintering temperature. After sintering at 900 °C, the alloy exhibited high density (99.8%), good compressive strength (1417.2 MPa) and excellent corrosion resistance. In addition, it had a lower elastic modulus (~69 GPa) than that of the biomedical alloy Ti–13Nb–13Zr (~80 GPa). In vitro experiments showed that the alloys sintered at either 800 °C or 900 °C promoted cell adhesion and proliferation. However, the alloy sintered at 700 °C inhibited cell proliferation, which was due to the greater release of Mg2+. Thus, the optimally-processed Ti-Nb-Zr-Mg alloy sintered at 900 °C shows immense potential as a biomedical material.

The Effect of Granulated Fe Cluster-doped CNTs Support on The Catalytic Performance of NiO Catalyst in the DRM Reaction

This study first demonstrated the possibility of the production of catalyst supports in the form of granules and tablets composed of nanoparticles of Fe atom cluster-doped CNTs using mini-mold forming and spark plasma sintering (SPS) techniques respectively. The pilot samples of the novel catalyst system containing 3% NiO active phase, synthesized on the granulated Fe cluster-doped CNTs carrier, were tested to determine their catalytic activity and coking resistance in the DRM reaction, in a wide range of temperatures up to 900oC. The developed novel catalyst systems’ samples were characterized before and after the catalyst reaction using SEM, EDX, XRD, and AES methods. It is shown that the temperature dependence of the catalytic activity of the 3% NiO catalyst, supported on the granulated Fe cluster-doped CNTs carrier, revealed two characteristic temperature ranges with different rates of efficiency. Particularly, at high reaction temperatures, starting from 700oC, the conversion rates of methane and carbon dioxide (42.4% and 45.6% respectively) have more than doubled at 850oC. Starting from 850oC to 900oC the latter tends to exceed the carbon dioxide conversion rate, and at 900oC it amounts to 95%.

Synthesis and Characterization of Luminescent Er3+-Doped Natural Fluorapatite

Ca10(PO4)6F2:xEr3+ (x = 0.1, 0.3 and 0.5) was synthesized using solid-state powder process (1150 °C, 1h), conventional sintering (1150 °C, 1h), and spark plasma sintering (SPS) techniques (1150 °C, 10 min, and 50 MPa). XRD analysis revealed that all samples are generally composed of fluorapatite (FAP) containing quartz as a minor phase, and the presence of Er2O3 peaks is becoming more evident as Er-doped increases. In the SEM microstructure images, non-diffused Er2O3 particles also increase with doping in powder and pellet samples. However, the PL analysis showed that the luminescence intensity did not increase proportionally with the doping content caused by the concentration quenching effect. FAP samples doped with 0.3 mol Er have higher luminescence intensity than 0.1 and 0.5 mol Er-doped samples. In addition, powder samples have the highest luminescence intensity due to increased luminescence intensity with increasing crystallite size. The characteristic 2H11/2 to 4I15/2 emission bands of Er3+ at ∼530 nm are seen in all samples. The maximum average lifetime was obtained in 125 μs in the powder sample with 0.3 mol Er. CIE color coordinates demonstrate the standard green color under 275 nm excitation; eventually, these phosphors can be utilized as green phosphors for optical applications.

Improving the Mechanical Properties of GPLs-SiAlON Composites by Microfluidization Technique as a New Approach to Dispersion of GPLs

Graphene platelets (GPLs) are frequently preferred as reinforcement material to improve the mechanical properties of many advanced technology ceramics, thanks to their superior properties. However, their reinforcement levels vary depending on whether they are homogeneously distributed in the matrix microstructure. This is generally controlled by the thickness (number of layers) of the GPLs. In general, single- or few-layer GPLs show high performance as reinforcement but are commercially expensive. This limits their large-scale use. This study aims to achieve the performance of the GPLs (GPLRef), which is determined to have a high mechanical reinforcement level but is quite expensive, by economically thinning other GPLs (C0-GPL) with similar platelet size but cheaper and thicker structure. For this purpose, the microfluidization technique, a new approach to the dispersion of GPLs, was applied. C0-GPL is exposed to 1, 2, 4 and 8 cycles of microfluidization process. Microfluidized GPLs were added to the SiAlON matrix at a ratio of 1.5 wt %, and the GPLs-SiAlON composites were sintered using the spark plasma sintering (SPS) technique. The platelet size of C0-GPL decreased as the number of applied microfluidization cycles increased. However, while this reduction in platelet size was not significant up to 2 cycles, it was very pronounced at 4 and 8 cycles. Raman analyses revealed that GPLs could be dispersed effectively for up to 4 cycles. After this point, the GPLs fragmented rather than thin as the number of cycles increased. GPLs slightly thinner than GPLRef could be obtained with 2 cycles of microfluidization (C2-GPL). Therefore, C2-GPL were more homogeneously dispersed in SiAlON matrix microstructure compared to GPLRef. As a result, both the through-plane and in-plane direction fracture toughness values of SiAlON matrix containing C2-GPL, which partially preserved the platelet size, were higher than those of GPLRef-SiAlON. The fracture toughness of SiAlON matrix composites containing 4 and 8 cycles of microfluidized GPLs were lower than that of GPLRef-SiAlON as an adverse effect of decreasing platelet size. It has been determined that the mechanical reinforcement performance of commercially expensive GPLRef can be achieved economically by applying 2 cycles of microfluidization to cost-effective C0-GPL.

Determinations of Ce solid solution mechanism and limit thermal conductivity of YTaO4 ceramics

x mol% CeO2-YTaO4 (x = 0, 3, 6, 9, 12) ceramics have been synthesized by the spark plasma sintering (SPS) technique. We focus on the changes in lattice distortion, bonding length, thermal conductivity, thermal expansion, and phase stability of the prepared samples. XRD, Raman, and XPS are used to determine the chemical valence and solid solution mechanism of Ce in the lattice of YTaO4, while its effects on thermal/mechanical properties are elucidated from microstructures. Y3+ is substituted via Ce3+, and all samples maintain a monoclinic phase. The limit thermal conductivity (1.2 W∙m−1∙K−1, 900 °C) is realized in 9 mol% CeO2-YTaO4, and the thermal expansion coefficients are increased to 10.2 × 10−6 K−1 at 1200 °C. Furthermore, the exceptional phase stability and mechanical properties of all samples indicate that they can provide good thermal insulation at high temperatures, and have higher working temperatures than the current YSZ thermal barrier coatings.

Mechanical and thermal behaviors of Ti36-Al16-V16-Fe16-Cr16 high entropy alloys fabricated by spark plasma sintering: An advanced material for high temperature/strength applications

Conventional superalloys possess high strength, high oxidation resistance and high creep resistance. Nonetheless, some lose strength at elevated temperatures, while others suffer high temperature oxidation and creep. This work was aimed at developing high entropy alloy (HEA) of Ti36-Al16-V16-Fe16-Cr16 at near equi molar configuration using spark plasma sintering technique which would be able to address the challenges of conventional superalloys. The powders were mixed with Turbular mixer at 69 rpm for 10 h. The sintering was carried out with the same sintering pressure of 40 MPa, time of 10 min, heating rate of 100°C/mins on all the samples. Only the sintering temperature was varied. The temperatures used included 700°C, 800°C, 900°C, 1000°C and 1100°C, respectively. The powders and sintered samples were characterized with Scanning electron microscopy connected to Energy Dispersive Spectroscopy and X-ray diffractometer. The mechanical properties were tested with Nano indenter using ASTM D785 standard; while the thermal stability was investigated with thermogravimetric analyzer. Results showed that HEA sintered at 1000°C possessed the best nanomechanical, thermal and microstructural properties while that sintered at 700°C had the weakest properties. The best developed alloy had an improved elastic modulus of 671.17 ± 50 GPa and 930.12 ± 38 GPa at darker flakey phase and white phase, respectively. It had creep resistance of 1.82%, densification of 98.96% and porosity of 1.04%. It was concluded that the developed alloy can perform much better than most superalloys in high temperature and high strength and applications.

Development, and characterisation of ultra-high-temperature ceramics composite (UHTC)

ABSTRACT Ultra high-temperature ceramic (UHTC) composite materials are physically and chemically stable at high temperatures (more than 2000°C) and in reactive environments. Generally, the family group of diboride, dicarbide, and dinitride are used as ultra-high temperature ceramic due to their high thermal conductivity and high melting point. The main aim of this paper is the development of zirconium diboride (ZrB2)-based UHTC and characterisation of their density, hardness, porosity, and work considered, three powder constituents B4C (35%), ZrB2 (55%), and Cr (10%) of particle size 30 μm, 15 μm, and 4 μm, respectively, the conventional sintering and spark plasma sintering technique is used for the development of composite. The results revealed that the relative density of conventionally sintered composite at 1600°C and 1700°C are 72% and 80%, respectively, and spark plasma sintered composite at 1900°C is 99.99%. The bulk density and apparent porosity of SPS composite at 1900°C are 4.73 g/cm3 and 4%, respectively. Similarly, bulk density and apparent porosity of conventionally sintered composite, at 1600°C are 2.49 g/cm3 and 30%, respectively, and at 1700°C is 2.89 g/cm3 and 27%, respectively. Furthermore, the hardness of the SPS composite at 1900°C is 2830 HV, while the hardness of conventionally sintered composite at 1700°C and 1800°C were 280 HV and 520 HV, respectively. Additionally, scanning electron microscopy was performed to observe the bonding and porosity in the microstructure of the UHTC.