Min Hold Research Articles

A proof-of-concept Bitter-like HTS electromagnet fabricated from a silver-infiltrated (RE)BCO ceramic bulk

A novel concept for a compact high-field magnet coil is introduced. This is based on stacking slit annular discs cut from bulk rare-earth barium cuprate ((RE)BCO) ceramic in a Bitter-like architecture. Finite-element modelling shows that a small 20 turn stack (with a total coil volume of < 20 cm3) is capable of generating a central bore magnetic field of > 2 T at 77 K and > 20 T at 30 K. Unlike resistive Bitter magnets, the high-temperature superconducting (HTS) Bitter stack exhibits significant non-linear field behaviour during current ramping, caused by current filling proceeding from the inner radius outwards in each HTS layer. Practical proof-of-concept for this architecture was then demonstrated through fabricating an uninsulated four-turn prototype coil stack and operating this at 77 K. A maximum central field of 0.382 T was measured at 1.2 kA, with an accompanying 6.1 W of internal heat dissipation within the coil. Strong magnetic hysteresis behaviour was observed within the prototype coil, with ≈30% of the maximum central field still remaining trapped 45 min after the current had been removed. The coil was thermally stable during a 15 min hold at 1 kA, and survived thermal cycling to room temperature without noticeable deterioration in performance. A final test-to-destruction of the coil showed that the limiting weak point in the stack was growth-sector boundaries present in the original (RE)BCO bulk.

High temperature vacuum brazing of tungsten to tungsten alloy with structural material

The present paper offers an overview of experimental research on the vacuum brazing procedure used to join tungsten-based refractory materials and tungsten alloy with SS316L (a structural material) at high temperatures. The objective of joining tungsten (W) to tungsten alloy material (WL10) and SS316L materials is to develop a joining technique for fabricating the helium-cooled divertor target relevant to a DEMO-like fusion reactor. These divertor fingers are expected to withstand an incident heat flux of 10 MW/m2 and to be cooled by helium jets in an environment of high pressure (10 MPa) and high-temperature (600 °C) helium gas. High-temperature vacuum brazing has been performed at temperatures exceeding 1000 °C using selective brazing fillers in the Gleeble Machine-3800 thermo-mechanical simulator to join W (tungsten) to WL10 alloy (tungsten + 1 % Lanthanum oxide). Furthermore, vacuum brazing of multilayer materials, such as W-WL10-SS316L, has been conducted at 1050 °C for a 3 min hold time using AMS 4777 filler material in a single run on the Gleeble machine. The brazed specimens have undergone testing for 500 thermal cycles from 950 °C to 815 °C on the Gleeble-3800 machine to pre-qualify the brazed joints. Non-destructive testing (NDT), including ultrasonic testing (UT), microstructural analysis, and mechanical characterization, is employed to assess the quality of the brazed joints. The study presents the experimental techniques and the results of the characterization.

Phase Transitions and Oxidation Behavior During Oxyacetylene Torch Testing of TaC–HfC Solid Solutions

Tantalum carbide (TaC) and hafnium carbide (HfC) have some of the highest melting temperatures among the transition metal carbides, borides, and nitrides, making them promising materials for high‐speed flight and high‐temperature structural applications. Solid solutions of TaC and HfC are of particular interest due to their enhanced oxidation resistance compared to pure TaC or HfC. This study looks at the effect of Hf content on the oxidation resistance of TaC–HfC sintered specimens. Five compositions are fabricated into bulk samples using spark plasma sintering (2173 K, 50 MPa, 10 min hold). Oxidation behavior of a subset of the compositions (100 vol% TaC, 80 vol% TaC + 20 vol% HfC, and 50 vol% TaC + 50 vol% HfC) is analyzed using an oxyacetylene torch for 60 s. The TaC–HfC samples exhibit a reduction in the oxide scale thickness and the mass ablation rate with increasing HfC content. The improved oxidation resistance can be attributed to the formation of a Hf6Ta2O17 phase. This phase enhances oxidation resistance by reducing oxygen diffusion and serving as a protective layer for the unoxidized material. The superior oxidation resistance of TaC–HfC samples makes these materials strong contenders for the development of high‐speed flight coatings.

Effect of subcritical water flash release processing on buckwheat flour properties.

Buckwheat (Fagopyrum esculentum) is rich in bioactive components. However, many of these components are trapped within cellular structures, making them inaccessible. Buckwheat flour was hydrothermally modified using subcritical water coupled with a flash pressure release (SCWF). The effects of the SCWF parameters (120, 140, and 160 °C and hold times of 0, 15, and 30 min) on the flour's structure, physicochemical, and functional properties were studied relative to the raw flour. Treatment deepened the flour color with increasing processing temperatures and hold times. Starch content remained unchanged though its granular structure was disrupted. SCWF treatments lowered total phenolic content compared with the raw flour, except for 160 °C-30 min, where total phenolic content increased by 12.7%. The corresponding antioxidant activities were found consistent with phenolic content. Soluble and insoluble dietary fiber amounts were not substantially influenced at 120 and 140 °C, whereas treatments at 160 °C (15 and 30 min hold) decreased soluble dietary fiber while increasing insoluble dietary fiber. Protein content increased 70-109% in some treatments, suggesting greater protein accessibility. Water-holding capacity significantly increased for flour treated at 120 °C, whereas only slight improvements occurred at 140 and 160 °C. Subcritical water flash processing can modify the compositional and functional properties of buckwheat flour depending on the choice of reaction conditions. Observed changes were consistent with alteration of the flour's cellular structure and allow some components to become more accessible. The resulting SCWF-modified buckwheat flours provide new food ingredients for potential use in ready-to-eat foods and spreads with improved health benefits. Published 2022. This article is a U.S. Government work and is in the public domain in the USA.

Influence of Ti addition on MX precipitation and creep-fatigue properties of RAFM steel for nuclear fusion reactor

As part of the research framework to improve the mechanical properties of the reduced activation ferritic/martensitic (RAFM) steels suitable for higher temperatures, the effects of Ti addition on microstructures and low cycle fatigue (LCF) properties have been investigated. The addition of 0.015 wt% Ti to conventional base RAFM steel (9.3Cr‒0.93W‒0.22V‒0.094Ta‒0.10C‒Fe) increased the volume fraction of MX particles (2.1–4.6%). Atom probe tomography results showed that Ti atoms were rarely partitioned to (V,Ta)-rich MX precipitates with the size of 4‒13 nm, and instead most Ti atoms were involved in the formation of TiC precipitates with the size of 2‒8 nm. The nano-sized TiC particles were homogeneously distributed with the highest population. The LCF property of the Ta/Ti-added RAFM steel was inferior to the base RAFM steel. The cyclic stress reduction rate (softening rate) was higher in the Ta/Ti-added RAFM steel due to a higher density of dislocations at the initial state. The 10 min hold time at the peak tensile strain was imposed on the LCF testing to add creep damage to the cumulative fatigue damage. The creep-fatigue life of the Ta/Ti-added RAFM steel was about 2 times longer than the base RAFM steel. These results indicated that Ti addition-induced nano-sized MX particles are highly resistant to creep damage rather than fatigue damage. The higher fraction of nano-sized TiC and (V,Ta)-rich MX particles was responsible for the substantial retention of fine laths with a high density of dislocations during creep. The cyclic softening mechanism was discussed in terms of microstructure evolution during LCF and creep-fatigue deformation to explain the contradictory creep and fatigue properties.

Impact of varying degrees of peripheral nerve blockade on experimental pressure and ischemic pain: adductor canal and sciatic nerve blocks in a human model of compartment syndrome pain

IntroductionEarly diagnosis of acute extremity compartment syndrome is crucial to timely surgical management. Pain is commonly used as an early diagnostic sign for acute extremity compartment syndrome, making regional anesthesia...

Thermal Preprocessing of Rapidly Solidified Al 6061 Feedstock for Tunable Cold Spray Additive Manufacturing

In this work, the influence of thermal pre-processing upon the microstructure and hardness of Al 6061 feedstock powder is considered through the lens of cold spray processing and additive manufacturing. Since solid-state cold spray processes refine and retain microstructural constituents following impact-driven and high-strain rate severe plastic deformation and bonding, thermal pre-processing enables application-driven tuning of the resultant consolidation achieved via microstructural and, therefore, mechanical manipulation of the feedstock prior to use. Microstructural analysis was achieved via X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, energy dispersive spectroscopy, and differential thermal calorimetry. On the other hand, nanoindentation testing and analysis were relied upon to quantify pre-processing effects and microstructural evolution influences on the resultant hardness as a function of time at 540 °C. In the case of the as-atomized powder, β-Mg2Si-, Al-Fe-, and Mg-Si-type phases were observed along polycrystalline grain boundaries. Furthermore, after a 60 min hold time at 540 °C, Al-Fe-Si-Cr-Mn- and Mg-Si-type intermetallic phases were also observed along grain boundaries. Furthermore, the as-atomized hardness at 250 nm of indentation depth was 1.26 GPa and continuously decreased as a function of hold time until reaching 0.88 GPa after 240 min at 540 °C. Finally, contextualization of the observations with tuning cold spray additive manufacturing part performance via powder pre-processing is presented for through-process and application-minded design.

Frozen-Phase High-Pressure Destruction Kinetics of Escherichia coli as Influenced by Application Mode, Substrate, and Enrichment Medium.

The synergistic effect of frozen-phase high pressure (HP) on the inactivation of E. coli ATCC 25922 cultures in suspension medium, Chinese bayberry juice (pH 3.0), and carrot juice (pH 6.5) was evaluated. The survivor count of E. coli remained at 3.36 log CFU/mL on a nonselective brain heart infusion (BHIA) medium, while no survivor was detected on a selective violet red bile agar (VRBA) medium after a 5 min hold pressure at 250 MPa in a frozen culture suspension. BHIA was suitable for safe testing of the injured E coli cells after HP treatment in frozen state. Frozen Chinese bayberry juice showed higher sensitivity to HP treatment for its matrix property with high sterilizing efficiency at 170 MPa. Two pulses exhibited a significant inactivation effect in frozen samples compared with one pulse, especially for the Chinese bayberry juice with different pressure levels. The destruction kinetics of HP pulse mode followed the first-order rate kinetics with a Zp value of 267 MPa in frozen carrot juice. Our results evaluated the influenced factors of frozen HP destruction effects, including the medium, substrate, and application mode. The frozen HP destruction kinetics of pulses afford us better understanding of the technology application in the food industry.

Reactive Spark Plasma Sintering of Y3Al5O12-MgAl2O4 Composites

In this study, Y3Al5O12-MgAl2O4 (YAG-Spinel) composites, with different molar ratios (1:1 and 1:3), were in-situ fabricated via reactive spark plasma sintering technique (RSPS). The Al2O3, MgO, and Y2O3 powders were used as starting materials. In-situ formation of YAG-Spinel composites was investigated according to the reaction 3.5 Al2O3 + MgO + 1.5 Y2O3 → Y3Al5O12 + MgAl2O4. Both synthesis and densification processes were accomplished in a single rsps cycle with one-step heating. The RSPS process was performed at the sintering temperature of 1300 ᵒC for 30 min hold time with a maximum uniaxial pressure of 90 MPa under vacuum conditions. The synthesized phases and microstructures were investigated by X-ray diffraction and field emission scanning electron microscopy. The unwanted phases such as YAP (YAlO3) in composites microstructure were removed using LiF additive. LiF was used as a sintering aid in the process of sintering. The in-situ synthesized YAG-Spinel composites exhibited no internal infrared transmittance over 2.5-25 µm infrared wavelength ranges.

PSVII-17 Use of a dimethyl carbonate extraction for rumen fluid volatile fatty acid quantification by gas chromatograph mass spectrometry

Abstract Analysis of rumen fluid volatile fatty acids (VFA) is typically conducted by injecting acidified aqueous rumen fluid into a gas chromatograph (GC) with a flame ignition detector (FID). Water in GC samples can lead to poor peak shape and to contamination of inlets, potentially causing sample carryover. Aqueous methods are not well suited for use in mass spectrometer (MS) detector systems. The objective of this project was to validate a dimethyl carbonate (DMC) extraction process and GCMS method for rumen VFA analysis. To perform the extraction, 100 µL of sample, KHSO4 (50 g/L), and 2-ethylbutyrate (internal standard; 0.86 mM) are added to a microcentrifuge tube (in order) followed by 1 mL of DMC. The mixture is thoroughly vortexed and centrifuged. The organic layer (top) is removed and placed in a GC vial. The DMC extract is injected (0.5 µL) into an Agilent 5977B GCMS (8:1 split injection) with a polar DB-FFAP column. The column was held at 105°C for 5 min, increased at 10°C/min to 150°C, then 65°C/min to 240°C, and held constant for 10 min. The assay is linear for acetate from approximately 2 mM to at least 130 mM and covers the expected values of rumen concentrations for the other VFA. Recovery of VFA from spiked rumen fluid was tested at three concentrations in rumen fluid from steers fed a finishing diet or grazing wheat pasture. Recovery was not affected by the diet of the animals (P &amp;gt; 0.19) or the amount of VFA spiked (P &amp;gt; 0.27) and averaged 99.9% for all VFA, with valerate being the lowest (95.9%). Including the 10 min hold at 240°C at the end of each run prevented carryover from sample to sample. This method appears to perform well in a GCMS system and accurately and precisely quantify rumen fluid VFA.

Bench scale batch steam explosion of Florida red and white grapefruit juice processing residues

Florida juice processors amassed 51,000 metric tons of grapefruit juice processing residues (GFPR) in the 2018-19 season. GFPR contain valuable compounds such as pectic hydrocolloids, peel oil, sugars, phenolics and flavonoids that are ultimately lost or destroyed when they are converted to low value animal feed and molasses. If these compounds could be isolated from GFPR rather than destroyed, they could be converted to high value products. In this work, red and white GFPR were subjected to steam explosion in a batch system at 130, 150 and 170°C and 1, 2, 4 and 8 min holding time to identify the conditions for maximum recovery of pectic hydrocolloids, peel oil, sugars, phenolics and flavonoids. Steam explosion at 170°C and an 8 min hold time resulted in the recovery of 56-85% of total available glucose and fructose and the volatilization of 68-98% of the available peel oil. Of the phenolics and flavonoids analyzed, 61-62% could be extracted using steam explosion. Maximum recovery of pectic hydrocolloids, estimated by galacturonic acid content, was 1.6446 g • 100 g−1 for red GFPR at 130°C – 8 min and 1.557 g • 100 g−1 for white GFPR at 150°C – 2 min.

Pectic hydrocolloids from steam-exploded lime pectin peel: Effect of temperature and time on macromolecular and functional properties.

Previously, we showed the weight average molecular weight (M w) and intrinsic viscosity ([ƞ]) of pectic hydrocolloids recovered from steam‐exploded citrus peel were low, suggesting fragmentation due to process temperature and/or time‐at‐temperature. We have tested this hypothesis on a commercial lime pectin peel, washed to remove soluble sugars and dried for stabilization, using a static steam explosion system. We examined temperatures of 120–150°C at 1–3 min hold times. Galacturonic acid recovery and M w ranged from 22% to 82% and 142–214 kDa, respectively. Recovery of most major pectic sugars increased concomitantly with galacturonic acid as temperature and time‐at‐temperature increased. [ƞ] ranged from 1.75 to 6.83 dl/g. The degree of methylesterification ranged from 66.5% to 72.1%. Tan (δ) (Loss modulus/Storage modulus; G″/G′) values of sugar–acid gels for 120–140°C treatments were <1.0. Ideal optimization analysis, where time, [ƞ], and percent recovery were maximized, identified processing conditions that favor either increased [ƞ] or percent recovery. The results presented here support our hypothesis that temperature and time‐at‐temperature affect M w and [η] of the recovered pectic hydrocolloids. These results also demonstrate that manipulating either temperature or time‐at‐temperature enables the production of structurally varied populations of pectic hydrocolloids. Based on optimization analysis, commercially viable values of [ƞ] can be obtained while recovering approximately 50% of the pectic hydrocolloids.

Correction to: Study of Static Steam Explosion of Citrus sinensis Juice Processing Waste for the Isolation of Sugars, Pectic Hydrocolloids, Flavonoids, and Peel Oil

In this work, citrus juice processing waste (CPW) from a local Florida processor was subjected to steam explosion using a static bench scale reactor at 130, 150, and 170 °C for 1, 2, 4, and 8 min hold times with the aim of identifying conditions necessary for maximizing the recovery of sugars, pectic hydrocolloids, flavonoids, and peel oil. Sugars in steam-exploded CPW, from two harvests each of Hamlin and Valencia oranges, were extracted using water or enzymatic hydrolysis. Hydrolysis resulted in a 32–39% increase in total sugars. While hydrolysis increased the amount of glucose or fructose, it did not necessarily reduce the temperatures and or hold times at which the maximum amounts of sugar were recovered. Peel oil in raw CPW was reduced by as much as 94% using steam explosion and has the potential to be recovered by condensation. More galacturonic acid was recovered at 150 and 170 °C and 1 min treatment time for both Hamlin and Valencia CPW but led to increased molecular weight, suspected to be caused by aggregation, and decreased intrinsic viscosity. The higher temperatures and hold times also allowed vastly improved recoveries of the otherwise insoluble flavanone glycoside, hesperidin, with a maximum yield of 64,611 ppm dw CPW. Other potential value-added materials such as hydroxycinnamates and the health-benefiting polymethoxylated flavones are also recoverable in high percent yields in the water washes after steam explosion. Estimates are provided of the value of these recoverable products in the CPW of the 2016–17 Florida citrus season.

High-pressure processing of usually discarded dry aged beef trimmings for subsequent processing

In this study, we investigated if the usually discarded trimmings from dry aged beef can be incorporated into raw fermented sausages as a substitute for fresh beef without altering any major characteristics. Dry aged trimmings were subjected to high-pressure processing (600 MPa, 3 min hold) to reduce the bacterial load, achieving a 3-log reduction. HPP-treated dry aged beef trimmings were then incorporated into raw fermented sausages (60% pork and 40% beef). Beef was substituted with trimmings in different concentrations (7.5, 12.5, 25, 50, 100%). Due to the substitution, the water content of the sausages was reduced depending on the amount of beef substituted. Consequently, the sausages with substituted beef, for example, 50 and 100%, achieved the same water content after 5.4 and 3.7 days, respectively, than control sausage at day 9. However, the substitution (100%) affected the fat content, which contributes to significant differences (p < .05) in firmness during ripening.

Electric current–assisted direct joining of silicon carbide

Conventional direct joining technologies are difficult to use with silicon carbide (SiC) materials, especially for fiber composite forms of SiC, because of the harsh conditions required. To reduce the temperature and/or process time required for the direct joining process, an electric current–assisted joining (ECAJ) method was studied. Joining of low–resistivity grade, nitrogen doped β-SiC was demonstrated at a relatively low nominal temperature of 1750 °C with a 10 min hold by enhancing the passage of current through the material. The joining mechanism is discussed in terms of localized overheating and accelerated self-diffusion at the interface. In the case of joining at 2160 °C for 1 min, rapid crystal growth of textured SiC was found at the interface. This study indicates that rapid ECAJ-based direct joining is a practical and appropriate method for joining SiC-based materials.

Synthesis of nano-phase ZrC by carbothermal reduction using a ZrO2–carbon nano-composite

Carbothermal reduction of Zr-sucrose gels powders into nano-phase ZrC, or ZrC-Zr(C,O) core-shell powders, via a composite of 2–4 nm sized ZrO2 and amorphous carbon, is described. Samples with 1.7–20 sucrose-carbon:Zr ratio gels heated to 1495 °C at 10 °Cmin−1, with 3 and 30 min hold time were studied in detail using; TG, XRD, SEM, TEM, STEM-EDX, and XPS with Ar+-ion etching. After 1495 °C, 3 min, the samples with 12-20C:Zr ratios yielded weakly agglomerated 30 to 40 nm sized ZrC particles, surrounded by a dense 5 nm thick shell of Zr(C,O). With 5C:Zr significant amounts of ZrO2 was present after heating at 1495 °C for 3 min, while after 30 min annealing, ZrC particles without residual amorphous carbon was obtained. Minor amounts of zirconia was found in most samples, which in similarity with the 5 nm Zr(C,O) shell, is believed to stem from post synthesis oxidation.

In-situ monitoring of inactivation of Listeria innocua under high hydrostatic pressure using electrical conductivity measurement

The effect of high hydrostatic pressure on electrical conductivity of samples of Listeria innocua ATCC 33090 bacterial suspension (~1010 CFU/ml) was investigated, to determine if its inactivation could be monitored via such measurements. HHP treatment was applied at 300, 400 and 500 MPa, and the electrical conductivity, temperature and pressure were continuously recorded during experiments. Microbiological concentrations were also monitored by plate-counting over a 60 min hold period. With increasing pressure the degree of cell damage increased resulting in higher final electrical conductivity and higher reduction in Listeria innocua CFU. The log reduction in bacterial counts increased with increasing conductivity ratio. Conductivity ratio increased during pressurization and holding, but did not change during depressurization, suggesting that little or no inactivation occurred during this phase. Data on conductivity ratio, calibrated against microbial count reduction could be used to fit to inactivation kinetics models. A log-linear model with tail was found to provide the best fit.

Machining of TiB&lt;sub&gt;2&lt;/sub&gt;- SiC Ceramic Composites through WEDM Process

In the present study Spark Plasma Sintering (SPS) technique is used to synthesis of particulate Ceramic Matrix Composites (CMCs). SPS is a type of hot pressing method and in this method, the rate of heating is from 100C to 1000C per minute with high densification. TiB2 (average size of 14 μm) particles were chosen as matrix and SiC (average size of 1 μm) particles were used as reinforcement. In the first stage of the study, synthesis of CMCs with TiB2 matrix and SiC reinforcement with varying volume% (0, 5, 10 and 15 vol.%) was carried out using Spark Plasma Sintering furnace available at IIT Madras in 1100°C, 40MPa and 10 min hold of time. But machining of CMCs from conventional machining processes is difficult especially to make complex and precise parts from CMCs. Hence, in the second stage of the work, Wire Electric Discharge Machining (WEDM) studies were carried out on the processed four composites by varying current (2, 3 and 4 A), Pulse on (Ton-30, 60 and 90 μs) and Pulse off time (Toff-5, 10 and 15 μs) as per Taguchi L9 orthogonal array. WEDM studies revealed that at 4A current, 60μs Ton and 5μs Toff gave maximum material removal rate (MRR) of 2.93 mm3/s, 2.27 mm3/s, 2.71 mm3/s and 0.62 mm3/s for CMC with 0% SiC, 5% SiC, 10% SiC, 15% SiC vol.% reinforcement respectively. To reduce material wastage during machining, kerf width is considered and in which 3A current, 90μs Ton and 5μs Toff gave the least kerf of 0.35 mm, 0.32 mm, 0.33 mm and 0.28 mm for 0% SiC, 5% SiC, 10% SiC, 15% SiC vol.% reinforcement respectively.

Microstructure evolution of warm deformed multilayered Al alloy sheet during brazing

Warm forming can improve the formability of Al alloy sheets that are used in heat exchanger production, but the effect of warm forming on the brazing performance of the sheet is not well understood. This investigation evaluates the brazing performance and corresponding microstructure evolution of a warm formed sheet comprised of an Al-Mn core alloy and an Al-Si clad alloy. Understanding the conditions that lead to the detrimental process of liquid film migration (LFM) during brazing is of particular interest. Warm forming was simulated by tensile tests performed between room temperature and 250 °C, and at strain rates between 7E-4 s −1 to 7E-2 s −1 . A brazing treatment consisting of a 3 min hold at 600 °C was simulated using differential scanning calorimetry. Brazing performance was evaluated by the ratio of the clad alloy solidification energy to the initial melting energy ( i.e. ΔH sol /ΔH melt ). The post-braze microstructure and ΔH sol /ΔH melt depended on strain, strain rate, and forming temperature. ΔH sol /ΔH melt was 0.5 or less when LFM occurred during brazing, but improved to 0.7 when the core alloy recrystallized. The dislocation density in the sheet was calculated using the Bergstrom hardening model; dislocation densities over which LFM and full core recrystallization occurred were distinct from one another. When LFM did not occur, isothermal solidification reduced the amount of clad alloy available for brazing by 23 %. It is concluded that the post-braze microstructure strongly depends on the sheet forming conditions, and that the driving force for LFM is the reduction of stored deformation energy.

Effect of Acid Etching Time and Concentration on Oxygen Content of Powder on the Microstructure and Elastic Properties of Silicon Carbide Densified by SPS

In this current paper, oxygen content of a fine particle size SiC (H. C. Starck UF 25 Silicon Carbide) and coarser particle size SiC (Saint Gobain Silicon Carbide) were modified by using different concentrations of HF for etching. Fully dense silicon carbide ceramics (>99% th. density) were produced by the spark plasma sintering technique at 1950 °C under an applied pressure of 50 MPa for 5 min hold with boron carbide and carbon addition. Archimedes method, scanning electron microscopy, and the ultrasound analysis were used to examined density, microstructure, elastic (E), shear (G), and bulk (K) moduli of dense silicon carbide ceramics to investigate the effect of oxygen impurities on the densification and the properties of silicon carbide. The results showed that high oxygen content is detrimental to the final density of SPS silicon carbide. When the oxygen content increased from 0.60 to 5.92 wt.%, the relative density decreased from 99.99% to 96%. For both SiC powders, by increasing the etching time, the grain size of SiC decreased. It means that the high oxygen caused grain growth. Ultrasound analysis results showed that the high oxygen content affected the elastic properties. SiC samples with the high oxygen content had a lower elastic moduli, shear moduli and bulk moduli. It was clear that increasing the oxygen content decreased the elastic properties.