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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Effect of Microstructure and Properties of Ni-WC Composite Coatings on Their Solid Particle Erosion Behavior

Metal matrix composites (MMCs) of WC in Co or Ni matrices are widely used due to their high wear resistance. Previous studies showed that tailoring the mechanical properties through optimum WC content can significantly extend the life cycle of MMCs. In this study, composite coatings of Ni with various WC content ranging from 10 to 55 vol.% were cold sprayed using agglomerated WCNi powders and two different sizes of Ni powders, − 10 + 4 (d{sub 50} = 7 µm) referred to as Ni(7) and − 35 + 15 (d{sub 50} = 25 µm) to as Ni(25). Microstructural characterization, including the deformed structure of Ni splats and retention and distribution of WC, was performed by scanning electron microscopy (SEM). Composite coatings were subjected to solid particle erosion following ASTM G76-13 standard. At low WC content coatings, erosion occurred primarily by plastic deformation of Ni matrices and knocking out of WC particles. At high WC concentrations, network distribution of compacted WCNi particles in the matrices led to a significant drop in erosion rates of coatings, due to a change in erosion mechanism from severe cutting and plowing of Ni and WC dislodging to WCNi splats spalling. Composite coatings sprayed using finer size Ni powder were usually more erosion resistant.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Microstructure development and properties of micro-alloyed copper, Cu-0.3Zr-0.15Ag, produced by electron beam additive manufacturing

A micro-alloyed copper powder, Cu-0.3Zr-0.15Ag wt.%, was produced using gas atomization reaction synthesis. Zirconium was added to copper to sequester the oxygen present as copper oxide surface films on the powder particles. The as-received powders, as well as the intentionally oxidized powders were used to fabricate solid test articles by electron beam powder bed fusion additive manufacturing. Dense samples fabricated from as-received powder demonstrated nominal UTS, yield, and elongation values at 260 MPa, 150 MPa, and 34%, respectively. The average electrical conductivity of these samples was measured at 95% of the international annealed copper standard (IACS). Samples fabricated from the oxidized powder exhibited nominal UTS, yield, and elongation of 241 MPa, 146 MPa, and 43%, respectively, with an electrical conductivity of 95 % IACS. During characterization, it was observed that, rather than forming nano-scale dispersoids, the Zirconia (ZrO 2 ) appeared as discontinuous stringers in the metallographic cross-sections that crossed grain and melt pool boundaries. This was rationalized by tracing the presence of the micro-alloying addition of elemental zirconium, which was found to react with surface oxides dissociated in the melt pool to form ZrO 2 , which then solidified on the surface of the melt pool through an allotropic transformation to monoclinic ZrO 2 in discontinuous films and spheroids ranging in size from nanometers to microns. This was confirmed by microscopic analysis of the tops of the melt pools. On subsequent melt passes, these ZrO 2 structures were displaced and redistributed within the melt pool.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Preload Characterization of Short Models of MQXF the Nb 3 Sn Low-β Quadrupole for the Hi-Lumi LHC

MQXF is the Nb3Sn Low-β Quadrupole magnet that the HL-LHC project is planning to install in the LHC interaction regions in 2026 as part of an upgrade to increase the LHC inte-grated luminosity by about a factor of ten. The magnet will be fab-ricated in two different lengths: 4.2 m for MQXFA, built in the US by the Accelerator Upgrade Project (AUP), and 7.15 m for MQXFB, fabricated by CERN. In order to qualify the magnet de-sign and characterize its performance with different conductors, cable geometries and pre-load configuration, five short model magnets, called MQXFS, were fabricated, assembled and tested. The latest model, MQXFS6, uses a new powder-in-tube (PIT) su-perconducting wire, featuring a bundle barrier surrounding the filaments. The coil and the support structure were equipped with strain gauges and optical fibres to monitor strain during assembly, cool-down and excitation. In this paper we further develop the conventional azimuthal preload analysis and introduce a new set of tools for MQXF coil pack characterization which we use to an-alyse the behaviour of MQXFS6 room temperature preload and to reanalyse all the short models tested at CERN. A comparison is made between all the studied magnets revealing new characteriz-ing preload parameters.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Evidence of Room Temperature Ferromagnetism in Zn{sub 1−x}Sn{sub x}S Thin Films

Tin (Sn)-doped zinc sulfide (Zn{sub 1−x}Sn{sub x}S) thin films at different tin (Sn) concentrations (= 0.00, 0.02, 0.05, and 0.08) were coated onto Corning 7059 glass substrates using the electron beam evaporation technique. The films were subjected to different characterization techniques to study the physical properties of the thin films. The structural properties of the films were studied using a powder X-ray diffractometer (XRD), and it was found that the films were cubic in structure without any impurity phases. The crystallite size increased with an increase of Sn concentration, and the mean crystallite size was 21 nm. The chemical composition and surface morphology of the films were studied using scanning electron microscopy (FE-SEM) with energy-dispersive analysis of X-rays (EDAX). Optical properties such as transmittance and absorbance were recorded using a diffuse reflectance spectroscope (UV–vis–NIR). All the films exhibited high optical transmittance of 85% in the visible region of the solar spectrum. The band gap of the films was calculated using Tauc’s relation, and it was found that it increased from 3.53 to 3.57 eV with an increase in the Sn doping concentration from x = 0.02 to x = 0.08. The room temperature photoluminescence studies of the films were recorded using a fluorescence spectrophotometer, and it was found that the films exhibited a prominent emission peak at 420 nm. The magnetic properties of the films and glass substrates at room temperature were studied using a vibrating sample magnetometer. From this, it was found that the films were weakly ferromagnetic at room temperature and the strength of magnetization increased with an increase of doping concentration from x = 0.02 to x = 0.05 and decreased at higher doping concentrations (x = 0.08). The films showed high magnetization at x = 0.05. The films at x = 0.05 exhibited the magnetization (M{sub s}), retentivity (M{sub r}), and coercive fields (H{sub c}) 18 × 10{sup − 6} emu/cm{sup 3}, 1.6 × 10{sup − 6} emu/cm{sup 3}, and 91.80 Oe, respectively.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Rheology improvement for silicon nitride and resin slurries for vat photopolymerization printing and sintering

This work presents the formulation, rheological characterization, and sintering of silicon nitride (Si₃N₄) slurries for vat photopolymerization (VPP) using digital light processing (DLP). Bimodal Si₃N₄ powder was dispersed into commercial photopolymer resin using two different dispersants with opposing effects on surface charge, resulting in varied slurry stability and flow behavior. Slurries were engineered to exhibit shear-thinning behavior suitable for VPP, and their flow properties were quantified using a power-law fluid model. The formulations achieved cure depths of approximately 40 µm and enabled printing of green bodies. Post-processing included thermal debinding and liquid-phase sintering, yielding primarily β-Si₃N₄ with a minor Y-Si-Al-O-N glass phase. The sintered parts reached ~85% of theoretical density and demonstrated a flexural strength of ~330 MPa. Microstructural analysis revealed closed porosity along with some defects related to powder agglomeration and interlayer adhesion. These findings provide insights into slurry formulation strategies for additive manufacturing of high-performance non-oxide ceramics.

Aerospace engineering↗
DOE OSTI2026

Quantum critical point followed by Kondo-like behavior due to Cu substitution in the itinerant antiferromagnet La 2 ⁢(Cu 𝑥 ⁢Ni 1−𝑥 ) 7

La 2 ⁢Ni 7 is an itinerant magnetic system with a small ordered moment of ∼ 0.1⁢µ 𝐵 /Ni and a series of antiferromagnetic (AFM) transitions at 𝑇 1 = 61.0K, 𝑇 2 = 56.5K, and 𝑇 3 = 42.2K. 𝑀 ⁡(𝐻), and 𝜌 ⁡(𝐻) isotherms as well as constant field 𝑀⁡ (𝑇) and 𝜌 ⁡(𝑇) measurements on single-crystalline samples manifest a complex, anisotropic 𝐻−𝑇 phase diagram with multiple phase lines. Here, in this study, we present the growth and characterization of single crystals of the La 2 ⁢(Cu 𝑥 ⁢Ni 1−𝑥 ) 7 series for 0 ≤ 𝑥 ≤ 0.181. We measured powder x-ray diffraction and composition, as well as anisotropic temperature- and field-dependent resistivity, temperature- and field-dependent magnetization, and temperature-dependent heat capacity on these single crystals. Using the measured data we infer a transition temperature-composition (𝑇−𝑥) phase diagram for this system to study the evolution of the AFM ordering upon Cu substitution. For 0 ≤ 𝑥 ≤ 0.097, the system remains magnetically ordered at base temperature with 𝑥 ≤ 0.012, showing signs of multiple AFM ordering temperatures. For the higher substitution levels 0.125 ≤ 𝑥 ≤ 0.181, there are no signatures of magnetic ordering, but anomalous features in resistance and heat capacity data are observed which are consistent with the Kondo effect in this system. The intermediate 𝑥 = 0.105 sample lies between the magnetic ordered and the Kondo regime and is in the vicinity of the AFM quantum critical point (QCP). Thus, La 2⁢ (Cu 𝑥 ⁢Ni 1−𝑥 ) 7 is an example of a small moment system that can be tuned through a QCP. Given these data combined with the fact that the La 2⁢ Ni 7 structure has kagomelike, Ni sublattices running perpendicular to the crystallographic 𝑐 axis, and a predicted 3⁢𝑑-electron flat band that contributes to the density of states near the Fermi energy, La 2 ⁢(Cu 𝑥 ⁢Ni 1−𝑥 ) 7 becomes a promising system to host and study exotic physics.

Das, Atreyee [Ames Laboratory, and Iowa State Univ↗
DOE OSTI2018

Towards Mixed Ionic and Electronic Conducting Li-Stuffed Garnets

Li-stuffed garnet-type Li 7 La 2.75 Ca 0.25 Zr 1.75 Nb 0.25 O 12 (LLCZNO) and Li 7+y La 2.75 Ca 0.25 Zr 1.75-y Nb 0.25 MyO 12 (M = Mn, Fe, Co, Ni; y = 0.1, 0.2, referred to as yM-LLCZNO) were synthesized in air by ceramic synthesis at different sintering temperatures. The resulting compositions were characterized for their phase formation and microstructure, and their ionic and electronic conductivities in air and 7% H 2 /N 2 . Powder X-ray diffraction showed that transition metal-doped LLCZNO garnets contain several impurity phases. The transition metal-substituted samples have lower conductivities than that of the parent LLCZNO. The electronic conductivities of selected transition metal-doped LLCZNO samples were found to be about 4 to 5 orders of magnitude lower than their corresponding ionic conductivity, highlighting the challenge to design single-phase mixed electronic and ionic conducting Li-stuffed garnets in both oxidizing and reducing atmospheres. The research area of single-phase mixed conducting Li-garnet is relatively unexplored at the moment, and a theoretical study will help to elucidate the underlying challenge in doping transition metal in Li-based garnets structure and its effect on transport properties.

25 ENERGY STORAGE↗
DOE OSTI2019

Controllable 3D Manufacturing System

Next generation Small Modular Reactor (SMR) requires new and improved techniques, instrumentations and strategies to deal with the anticipated high radiation and high temperature environment (esp. in reactors). Component manufacturing technologies will be required that take full advantage of the new 3-D printing methods employed by additive manufacturing technologies. These manufacturing methods must be capable of producing components or sub components on a limited production basis and with nuclear quality. Based on our success in developing a variety of award-winning high energy and high power ultrafast fiber lasers and our pioneered work in fs laser 3D manufacturing (US patents, 9643361 and 9770760), PolarOnyx proposes to use tunable fiber lasers to develop smart AM & SM system to make nuclear quality components for SMR. In Phase I, we have achieved critical milestones and experimentally demonstrated the most critical functions of the proposed controllable laser AM: • Developed and investigated a series of NDI sensing technologies. Combination of IR thermal image and high resolution visible camera provides a powerful tool to characterize thermal distribution and defects. • Built an in-line laser induced breakdown spectroscopy (LIBS) to real time detect compositions of powder and parts, and melting temperature of the melting pool. It proves the LIBS is a very powerful tool to precisely guide the process. • Filed a patent (Application number 16378485) for integrating IR and visible images and LIBS for intelligent AM system. • Developed control algorithm and proved it works well for overhang experiment. • Achieved high density (>99%) and excellent mechanical properties. • Succeeded in developing a working and reliable calibration method to extract true temperature distribution during AM process. • Demonstrated spatial and temporal pulse shaping methods, and impact on microstructures. • Filed one utility patent • Laid out a solid path for phase II to work on controllable 3D manufacturing system development and optimization and to make components with nuclear quality. Our proprietary fs fiber laser based AM processing offers an ultimate solution for manufacturing high temperature components with high strength for nuclear systems. The 3D AM system in conjunction with the intelligent sensing and control is energy efficient and cost effective for the growing nuclear industries. Successful development of the proposed AM technology will provide a vital tool to solve existing and potential issues. This technology will be directly applied in the 3D printing area with combined market share of $10(s) of billions. The achievement in this research will have significant and wide social, scientific, and economic impacts by providing affordable low cost intelligent AM/SM systems, laser micromachining systems, improving energy efficiency, and reducing fabrication and operational cost. Having demonstrated the proof of concept in Phase I, we will prototype the controllable AM/SM system and investigate the efficiency and qualification of fabricating various nuclear quality components in Phase II.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

3D Printing Catalytic Electrodes for Solar-Hydrogen Devices

Hydrogen production through water-splitting systems showed promising pathway to achieve <$2/kg cost target set by Department of Energy (DOE). As far, most efforts have been devoted to new electrocatalytical materials discovery. In contrast, the impact of architecture of the electrocatalysts as well as mass transport within the gas diffusion layers has not been well explored. In this project, we developed a new ink formulation with earth-abundant elements nickel and molybdenum (NiMo) for catalytical 3-dimentional (3D) electrodes in water-splitting devices. The NiMo electrodes fabricated via additive manufacturing have been characterized and tested. The architecture, morphology and compositions of the NiMo electrodes have been confirmed by Scanning Electric Microscopy (SEM) and Powder X-Ray Diffraction (XRD). We have demonstrated that the catalyst precursor survived the whole fabrication and post-treatment process. Furthermore, the NiMo 3D electrodes in this study exhibited state-of-art hydrogen evolution reaction (HER) performance, ~ 60 mV over potential for over 24 hours operation. The high performance of the 3D catalytical electrodes is attributed to large roughness factors (RF) of the electrodes and highly efficient mass transport. This study is in line with DOE initiative H2@Scale and national energy security missions at LLNL.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Tungsten Foils and Composites for Fusion Applications - Mechanical Testing

Tokamak fusion reactors ultimately should deliver safe, clean, and abundant energy provided that materials and plasma challenges continue to be overcome. Materials that can withstand large heat fluxes and mechanical loads while undergoing intense irradiation are needed for the plasma-facing components of these reactors and are still undergoing development. Tungsten composites are candidates for this purpose; they have low sputtering yields, high melting points, and may be more ductile than pure tungsten. However, the mechanical properties of tungsten composites are not yet well characterized. Tungsten foils produced using severe plastic deformation, e.g. cold rolling, have shown considerable promise for these applications as they may be more ductile than tungsten produced using powder metallurgy alone. Changes to the mechanical properties of tungsten foils have been suggested to be correlated with ultra-fine grained or nanocrystalline microstructures created by severe plastic deformation. Tungsten foils with larger amounts of plastic deformation, i.e. thinner foils, have been shown to have smaller grain sizes and a more pronounced texture in (100) <011>. The grain size and structure of foils with differing degrees of plastic deformation are therefore likely to differ significantly and the foils will likely exhibit very different mechanical properties. To fabricate tungsten foils into a useful structural material for high temperature fusion applications, layered composites are currently being examined. These composites integrate the excellent functional characteristics of tungsten foils with an interlayer such as steel that may improve ductility and toughness. To engineer and optimize layered composites, the mechanical properties of tungsten foils with differing thicknesses and degrees of plastic deformation must be characterized, both pre- and post-irradiation.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Crystalline phase transitions and water-soluble complexes of copper(Ⅰ) 2-hydroxyethanethiolate

We report the coordination polymer copper(I) 2-hydroxyethanethiolate, (CuSCH 2 CH 2 OH) n , though insoluble in all common solvents, dissolved readily in basic aqueous solutions of the thiolate anion (HOCH 2 CH 2 S – ) of 2-mercaptoethanol to form a single species: the tetranuclear cluster [Cu 4 (μ-SCH 2 CH 2 OH) 6 ] 2– . From this solution were grown X-ray quality single crystals of copper(I) 2-hydroxyethanethiolate. This compound underwent a hitherto unknown crystal phase transition at ca. 6 °C, from point group P2 1 2 1 2 1 to Pna2 1 , with noticeable changes in the geometry of the Cu-S layer and in the orientation of the alkylthiolate side chains. When the bulky base tetrabutylammonium hydroxide was employed in the aqueous thiolate solution used to dissolve (CuSCH 2 CH 2 OH) n , the water-soluble polynuclear copper(I) complex bis(tetrabutylammonium) hexakis(μ-2-hydroxyethanethiolato) tetracuprate(I), [(C 4 H 9 ) 4 N] 2 [Cu 4 (μ-SCH 2 CH 2 OH) 6 ], could be isolated as X-ray quality crystals. Structural characterization of this complex revealed a tetrahedral arrangement of copper(I) centers with thiolates bridging the edges of the tetrahedra. On standing, this complex degraded to a larger polynuclear Cu(I) sulfide cluster.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Microstructure characterization of electric field assisted sintering (EFAS) sintered metallic and ceramic materials using local thermal diffusivity measurement

Electric Field Assisted Sintering (EFAS, also referred to as spark plasma sintering) is a powerful technology for the consolidation of powder materials. The high heating rate during the sintering process is critical for minimizing energy consumption, but it can also cause microstructure heterogeneities in sintered parts, such as spatially varied porosity. The examination of localized porosity usually requires the use of a scanning electron microscope with a carefully prepared surface. In this paper, photothermal radiometry is used to measure local thermal diffusivity and extract localized porosity of EFAS-sintered parts by using a percolation-threshold model. Applying this approach, we identified the radial position-dependent porosity variation in EFAS parts, which is likely formed due to the large temperature gradient during the sintering process. This approach has a unique advantage because it can measure samples with minimal or no surface preparation, enabling the possibility of in situ characterization in EFAS with proper system modification. Necessary modifications on the measurement approach for EFAS deployment and in situ characterization are also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Ultrasonic Characterization of Spatially Varying Material Properties in Metal Components Fabricated by Additive Manufacturing

We investigated the sensitivity of ultrasonic measurements to changes in the operating conditions during additive fabrication for 316L stainless steel samples by selective laser melting. We found that the velocity of the ultrasound propagation positively correlates with the energy density used to melt layers of metal powder during the fabrication. In the range of the investigated conditions, the faster ultrasonic propagation, observed with the increase in the energy density, was shown to correspond to the improved hardness and the modulus of 316L stainless steel. Overall, our results indicate the feasibility of ultrasonic characterization of heterogeneities in the material properties of metal components produced by additive manufacturing.

Walton, Kenneth↗
DOE OSTI2021

Cs absorption capacity and selectivity of crystalline and amorphous Hf and Zr phosphates

Removal of radioactive Cs from sodium-rich solutions is a technical challenge that goes back to post World War II nuclear waste storage and treatment; and interest in this topic was reinvigorated by the Fukushima-Daiichi nuclear power plant disaster, 10 years ago. Since the 1960's there has been considerable focus on layered Zr phosphates as robust inorganic sorbents for separation of radionuclides such as Cs. Here we present synthesis and characterization, and direct comparison of Cs sorption capacity and selectivity of four related materials: 1) crystalline α-Zr phosphate and α-Hf phosphate, and 2) amorphous analogues of these. Powder X-ray diffraction, thermogravimetry, solid-state 31P magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy, and compositional analysis (inductively coupled plasma optical emission spectroscopy and mass spectroscopy, ICP OES and ICP MS) provided formulae; respectively M(HPO4)2∙1H2O and M(HPO4)2∙4H2O (M = Hf, Zr) for crystalline and amorphous analogues. Maximum Cs loading, competitive Cs-Na selectivity and maximum Cs-Na loading followed by the above characterizations plus 133Cs MAS-NMR spectroscopy revealed that amorphous analogues are considerably better Cs-sorbents (based on maximum Cs-loading and selectivity over Na) than the well-studied crystalline Zr-analogue. Additionally, crystalline α-Hf phosphate is better Cs-sorbent than crystalline α-Zr phosphate. All these studies consistently show that Hf phosphate is less crystallize than Zr phosphate, when obtained under similar or identical synthesis conditions. We attribute this to lower solubility of Hf phosphate compared to Zr phosphate, preventing ‘defect healing’ during the synthesis process.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

X-ray diffraction under grazing incidence conditions

Material properties frequently relate to structures at or near surfaces, particularly in thin films. As a result, it is essential to understand these structures at the molecular and atomistic levels. The most accurate and widely used techniques for characterizing crystallographic order are based on X-ray diffraction. When dealing with thin films or interfaces, standard approaches, such as single crystal or powder diffraction, are not suitable. However, X-ray diffraction under grazing incidence conditions can provide the required information. Here, in this Primer, grazing incidence X-ray diffraction (GIXD) is comprehensively introduced, starting from basic considerations on X-ray diffraction at crystals with reduced dimensionality and the optical properties of X-rays, followed by a more in-depth description of an experimental performance, including X-ray sources, goniometers and detectors. Experimental errors, limitations and reproducibility are discussed. Various applications, from highly ordered inorganic single crystal surfaces to weakly ordered polymer thin films, are presented to illustrate the potential of GIXD. Data visualizations, representations and evaluation strategies are summarized, based on the example of anthracene thin films. The Primer compiles information relevant to perform high-quality GIXD experiments, evaluate data and interpret results, to extend knowledge about X-ray diffraction from surfaces, interfaces and thin films.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Controlled release of losartan from acid- and heat-treated halloysite nanotubes

In this work, a simple method was used to sustained release of losartan (LOS) as a high blood pressure-controller drug using halloysites (HNT) as a carrier. The present work can be considered as an effective method because of using HNT as a natural source, which is available, inexpensive, safe with specific structure that led to release of drug, gradually. This carrier was improved by calcination and etching processes and their effect was investigated on loading amount and in vitro release of drug from HNT. The products were characterized by various analyses such as: BET (Brunauer–Emmett–Teller), TG (thermal gravimetry), TEM (transmission electron microscopy), and XRD (X-ray powder diffraction). According to the studies, two processes improving had no effect on structure and morphology of HNT and only increased the lumen size of them. It should be noted, removal water molecules through calcination had binary effect on halloysites: enlargement of lumen and decreasing the drug loading. Besides, release rate was investigated and it showed that maximum and minimum release rate of LOS are assigned to simple HNT and etched-HNT (EHNT), respectively. Kinetics studies confirmed that releasing the LOS molecules from HNT followed by diffusion process that is identified as Fickian diffusion.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Synthesis and characteristics of porous ceramic tubes: a comparison of centrifugal casting and cold isostatic pressing methods

Short porous ceramic tubes in small quantities are needed for membrane-related research and development efforts and can be synthesized by centrifugal casting (CC) or cold isostatic pressing (CIP) methods. Here, this work evaluates the characteristics of porous ceramic tubes prepared by both methods and provides a strategy for selecting the proper method for ceramic tube fabrication, depending on its application. Samarium-doped ceria (SDC) with an average crystallite size of 10 nm was synthesized by a citrate method and used to make porous SDC tubes by the CC and CIP methods under different conditions. Porous SDC tubes were prepared from an aqueous suspension of the SDC powder with polyvinyl alcohol (PVA) using a cylindrical metallic mold, centrifugated at 4000–6000 rpm, followed by sintering in 1200–1500 °C. SDC tubes were also made by the CIP method from the SDC powder placed inside a cylindrical rubber bag followed by isostatic compression at 1379 bar. The pore structure of the SDC tubes was characterized by helium permeation and liquid nitrogen Archimedes method. Due to high compression pressure giving a low porosity green tube, the CIP method with lower sintering temperature produces SDC tubes with much lower porosity and average pore size and similar tortuosity compared to the CC methods. The CIP method should be used to prepare low porosity or dense ceramic tubes, and the CC method should be used for preparing high-porosity ceramic tubes or tubes with pore gradient tube wall.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Synthesis, Crystal Structure, Electrochemical Properties, and Biological Activity of 2-((1H-Benzimidazol-2-yl)methylamino)acetic Acid

A water soluble compound, (2-((1H-benzimidazol-2-yl)methylamino)acetic acid, BIGH, has been synthesized and structurally characterized by elemental analysis, IR and UV spectroscopies, {sup 1}H-NMR, thermogravimetric and differential thermal analyses, and single crystal and powder X-ray diffraction. BIGH can act as a flexible planar ligand with three potential coordination sites. It crystallizes in a monoclinic system with the sp. gr. P2{sub 1}/c with the unit cell parameters, a = 9.3764(7) Å, b = 11.5031(8) Å, c = 10.0543(6) Å, and Z = 4. The crystal structure was stabilized through inter-molecular hydrogen bonds. The anti-microbial activity of the compound has been studied against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus, which showed a good activity against Bacillus subtilis. Cyclic voltammogram of the compound shows that it is a redox-active molecule.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗