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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two BaCO3 sheets oriented in the (0, 0, 1) direction. Ba2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Ba–O bond lengths are 2.77 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.31 Å. O2- is bonded in a single-bond geometry to two equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 is Potassium chlorate structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.70–2.89 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 crystallizes in the trigonal R3m space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine equivalent O2- atoms. There are three shorter (2.77 Å) and six longer (2.91 Å) Ba–O bond lengths. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.30 Å. O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.78–2.91 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 is Calcite structured and crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Ba2+ is bonded to six equivalent O2- atoms to form corner-sharing BaO6 octahedra. The corner-sharing octahedral tilt angles are 62°. All Ba–O bond lengths are 2.73 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.31 Å. O2- is bonded in a distorted trigonal planar geometry to two equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 is Calcite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to six O2- atoms to form distorted corner-sharing BaO6 octahedra. The corner-sharing octahedra tilt angles range from 48–68°. There are a spread of Ba–O bond distances ranging from 2.71–2.76 Å. In the second Ba2+ site, Ba2+ is bonded to six O2- atoms to form distorted corner-sharing BaO6 octahedra. The corner-sharing octahedra tilt angles range from 48–68°. There are a spread of Ba–O bond distances ranging from 2.70–2.77 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ba2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ba2+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one C4+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one C4+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to eight equivalent O2- atoms to form edge-sharing BaO8 hexagonal bipyramids. There are four shorter (2.72 Å) and four longer (2.97 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded in a 2-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.64–3.06 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.29 Å) and two longer (1.30 Å) C–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCO3 by Materials Project

BaCO3 is Potassium chlorate structured and crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.08 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1993

Ellipsometric study of ambient-produced overlayer growth rate on YBa2Cu3O(7-x) films

An ellipsometric study of ambient-reaction-produced BaCO3 overlayer growth on laser-ablated YBCO is presented as a function of time. The effects of the anisotropy of YBCO on the ellipsometric data inversion process are discussed, and it is concluded that with certain restrictions on the data acquisition method, the anisotropic substrate can be adequately modeled by its isotropic pseudodielectric function for the purpose of overlayer thickness estimation. It is found that after an initial period of rapid growth attributed to the chemical reaction of the exposed surface bonds, the BaCO3 overlayer growth is linear at 1-2 A per day. This slow growth rate is attributed to the complexity of the BaCO3-forming reaction, together with the need for ambient reactants to diffuse through the overlayer.

Sieg, Robert M.↗
NASA NTRS1988

Chemical durability of high-temperature superconductor YBa2Cu3O(7-x) in aqueous environments

The stability of YBa2Cu3O(7-x) in water and 100-percent humidity has been investigated at three temperatures, using pH measurements, X-ray diffraction, and scanning electron microscopy. The oxide-ceramic superconductor is highly unstable; it reacts rapidly with water and degrades in moisture. Dissolution of the oxide perovskite in water is highly incongruent. The corrosion products are found to be BaCO3, CuO, O2, etc. Barium hydroxide is first formed and further reacts with atmospheric CO2 to form needle-shaped crystals of BaCO3. For any practical applications, devices made from these materials would have to be protected with an impermeable coating to prevent deterioration from atmosphere.

Bansal, Narottam P.↗
NASA NTRS1988

Improved synthesis of ceramic superconductors with alkaline earth peroxides - Synthesis and processing of Ba2YCu3O(7-x)

Synthesis processes for the preparation of ceramic conductors Ba2YCu3O(7-x) from BaO2 or BaCO3 in flowing O2 or N2 are described, and the characteristics of the materials produced in these processes are compared. Results of EDAX, XRD, SEM, and dc resistivity analyses demonstrated that superconducting materials made from BaO2 were more homogeneous, denser, and more metallic than materials produced from BaCO3, because of the higher reactivity of BaO2. Potential applications of this processes are discussed.

Hepp, A. F.↗
NASA NTRS1983

High-temperature molten salt thermal energy storage systems for solar applications

Experimental results of compatibility screening studies of 100 salt/containment/thermal conductivity enhancement (TCE) combinations for the high temperature solar thermal application range of 704 deg to 871 C (1300 to 1600 F) are presented. Nine candidate containment/HX alloy materials and two TCE materials were tested with six candidate solar thermal alkali and alkaline earth carbonate storage salts (both reagent and technical grade of each). Compatibility tests were conducted with salt encapsulated in approx. 6.0 inch x 1 inch welded containers of test material from 300 to 3000 hours. Compatibility evaluations were end application oriented, considering the potential 30 year lifetime requirement of solar thermal power plant components. Analyses were based on depth and nature of salt side corrosion of materials, containment alloy thermal aging effects, weld integrity in salt environment, air side containment oxidation, and chemical and physical analyses of the salt. A need for more reliable, and in some cases first time determined thermophysical and transport property data was also identified for molten carbonates in the 704 to 871 C temperature range. In particular, accurate melting point (mp) measurements were performed for Li2CO3 and Na2CO3 while melting point, heat of fusion, and specific heat determinations were conducted on 81.3 weight percent Na2CO3-18.7 weight percent K2CO3 and 52.2 weight percent BaCO3-47.8 weight percent Na2CO3 to support future TES system design and ultimate scale up of solar thermal energy storage (TES) subsystems.

Petri, R. J.↗
NASA NTRS1987

Evidence for superconductivity above 40 K in the La-Ba-Cu-O compound system

An apparent superconducting transition with an onset temperature above 40 K has been detected under pressure in the La-Ba-Cu-O compound system synthesized directly from a solid-state reaction of La2O3, CuO, and BaCO3 followed by a decomposition of the mixture in a reduced atmosphere. The experiment is described and the results of effects of magnetic field and pressure are discussed.

Chu, C. W.↗
NASA NTRS1988

Advantages of barium peroxide in the powder synthesis of perovskite superconductors

This paper compares reaction chemistry, material processing, and material characteristics for the solid state reaction using BaCO3 or BaO2 in the synthesis of perovskite superconductors. Results are presented for weight loss and X-ray diffraction, sample morphology and homogeneity as monitored by SEM and EDS, and the superconductivity critical temperature and ac susceptibility. Greater mass density, increased sample homogeneity, lower resistance, and improved reproducibility for material are found when BaO32 is used.

Hepp, A. F.↗
NASA NTRS1988

Characterization of Ba2YCu3O(7-x) prepared in an inert atmosphere

Reaction data, X-ray data, and critical temperature measurements have been used to show that superconducting Ba2YCu3O(7-x) can be produced in an inert atmosphere using BaO2 as the barium source. Weight loss data are presented for samples produced in O2 and N2. The use of BaO2 is found to result in decreased levels of intergrain BaCO3. The necessity for total inert atmosphere handling and tighter control of the carbon content of starting materials is pointed out. It is shown that materials made with BaO2 and handled in inert atmospheres can be used to improve the J sub c of melt processed materials.

Hepp, A. F.↗
NASA NTRS1990

Synthesis of Y1Ba2Cu3O(sub x) superconducting powders by intermediate phase reaction

One of the more striking problems for the synthesis of the Y1Ba2Cu3Ox compound is the high-temperature decomposition of the BaCO3. This compound is present as raw material or as an intermediate compound in chemical processes such as amorphous citrate, coprecipitation oxalate, sol-gel process, acetate pyrolisis, etc. This fact makes difficult the total formation reaction of the Y1Ba2Cu3Ox phase and leads to the presence of undesirable phases such as the BaCuO2 phase, the 'green phase', Y2BaCuO5 and others. Here, a new procedure to overcome this difficulty is studied. The barium cation is previously combined with yttrium and/or copper to form intermediate compounds which can react between them to give Y1Ba2Cu3Ox. BaY2O4 and BaCu2O3 react according to the equation BaY2O4+3BaCu2O3 yields 2Y1Ba2Cu3Ox. BaY2O4 is a stable compound of the Y2O3-BaO system; BaCu2O3 is an intimate mixture of BaCuO2 and uncombined CuO. The reaction kinetics of these phases have been established between 860 and 920 C. The phase evolution has been determined. The crystal structure of the Y1Ba2Cu3Ox obtained powder was studied. According to the results obtained from the kinetics study the Y1Ba2Cu3Ox the synthesis was performed at temperatures of 910 to 920 C for short treatment times (1 to 2 hours). Pure Y1Ba2Cu3Ox was prepared, which develops orthorombic type I structure despite of the cooling cycle. Superconducting transition took place at 91 K. The sintering behavior and the superconducting properties of sintered samples were studied. Density, microstructure and electrical conductivity were measured. Sintering densities higher than 95 percent D(sub th) were attained at temperatures below 940 C. Relatively fine grained microstructure was observed, and little or no-liquid phase was detected.

Moore, C.↗
NASA NTRS1993

Room temperature degradation of YBa2Cu3O(7-x) superconductors in varying relative humidity environments

An aging study was performed to determine the stability of YBa2Cu3O(7-x) ceramics in humid environments at 20 C. In this study, fired ceramic specimens were exposed to humidity levels ranging from 30.5 to 100 percent for 2-, 4-, and 6-week time intervals. After storage under these conditions, the specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrical resistance measurements. At every storage condition evaluated, the fired ceramics were found to interact with H2O present in the surrounding environment, resulting in the decomposition of the YBa2Cu3O(7-x) phase. XRD data showed that BaCO3, CuO, and Y2BaCuO5 were present after aging and that the peak intensities of these impurity phases increased both with increasing humidity level and with increasing time of exposure. Additionally, SEM analyses of the ceramic microstructures after aging revealed the development of needle-like crystallites along the surface of the test specimens after aging. Furthermore, the superconducting transition temperature T(sub c) was found to decrease both with increasing humidity level and with increasing time of exposure. All the specimens aged at 30.5, 66, and 81 percent relative humidity exhibited superconducting transitions above 80 K, although these values were reduced by the exposure to the test conditions. Conversely, the specimens stored in direct contact with water (100 percent relative humidity) exhibited no superconducting transitions.

Hooker, M. W.↗
NASA NTRS1996

Solid State Synthesis and Properties of Monoclinic Celsian

Monoclinic celsian of Ba(0.75)Sr(0.25)Al2Si2O8 (BSAS-1) and B(0.85)Sr(O.15)Al2Si2O8 (BSAS-2) compositions have been synthesized from metal carbonates and oxides by solid state reaction. A mixture of BaCO3, SrCO3, Al2O3, and SiO2 powders was precalcined at approx. 900-940 C to decompose the carbonates followed by hot pressing at approx. 1300 C. The hot pressed BSAS-1 material was almost fully dense and contained the monoclinic celsian phase, with complete absence of the undesirable hexacelsian as indicated by x-ray diffraction. In contrast, a small fraction of hexacelsian was still present in hot pressed BSAS-2. However, on further heat treatment at 1200 C for 24 h, the hexacelsian phase was completely eliminated. The average linear thermal expansion coefficients of BSAS-1 and BSAS-2 compositions, having the monoclinic celsian phase, were measured to be 5.28 x 10(exp -6)/deg C and 5.15 x 10(exp -6)/deg C, respectively from room temperature to 1200 C. The hot pressed BSAS-1 celsian showed room temperature flexural strength of 131 MPa, elastic modulus of 96 GPa and was stable in air up to temperatures as high as approx. 1500 C.

Bansal, Narottam P.↗