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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Interaction of NaCl/g/ and HCl/g/ with condensed Na2SO4

Na2SO4(l)-NaCl(g) interactions were studied at a total pressure of one atmosphere of air or oxygen for various temperatures of Na2SO4(l) and for various partial pressures of NaCl(g) and H2O(g). Mass spectrometric sampling techniques were used to identify and monitor gas phase species. Continuous recording thermomicrogravimetric measurements were conducted to determine condensed phase weight change rates. Experimental measurements were supplemented with thermodynamic calculations. Numerous experiments were performed at sample temperatures of 900 and 1000 C with 300 ppm NaCl(g). In these experiments, the reproducibility of the Na2SO4 vaporization weight loss rate and initial weight gain upon addition of NaCl(g) were found to be satisfactory. It was found that the addition of NaCl(g) to air flowing over Na2SO4(l) at 900 and 1000 C enhances the rate of weight loss of the Na2SO4(l). This enhancement increases when H2O(g) is also added to the air flow.

Stearns, C. A.↗
NASA NTRS1977

Interaction of NaCl(g) and HCl(g) with condensed NA2SO4

The interaction of Na2SO4(l) with NaCl(g), HCl(g) and H2O(g) was studied in atmospheric pressure flowing air and oxygen at Na2SO4(l) temperatures of 900 and 1000 C. Thermomicrogravimetric and high pressure mass spectrometric sampling techniques were used. Experimental results establish that previously reported enhanced rates of weight loss of Na2SO4(l) in the presence of NaCl(g) are due to the reaction: Na2SO4(c) + 2HCl(g) = 2NaCl(g) + SO2(g) + H2O(g) + 1/2O2(g) being driven to the right in flowing gas systems. The HCl(g) is the product of hydrolysis of NaCl caused by small but significant amounts of H2O(g) present in the system. Thermochemical calculations are used to show that even with sub-ppm levels of H2O(g) present, significant quantities of HCl(g) are produced.

Stearns, C. A.↗
NASA NTRS1983

Effect of the amount of Na2SO4 on the high temperature corrosion of Udimet-700

The corrosion of Udimet-700, coated with different doses of Na2SO4, was studied in an isothermal thermogravimetric test in the temperature range 900 to 950 C. The weight gain curve is characterized by five distinct stages: an initial period of linear corrosion; an induction period; a period of accelerated corrosion; a period of decelerating corrosion; and a period of parabolic oxidation. The time required for the failure of the alloy increases with an increase in the amount of Na2SO4, reaches a peak and then decreases with further increase in the amount of Na2SO4. For low and intermediate doses (0.3 to 2.0 mg/sq cm), the catastrophic failure of the material occurs by the formation of Na2MoO4 and interaction of the liquid Na2MoO4 with the alloy. For heavy doses, the degradation of the material is due to the formation of large amounts of sulfides.

Misra, A. K.↗
NASA NTRS1984

Effects of SO2 and SO3 on the Na2SO4 induced corrosion of nickel

The effects of SO2 and SO3 in the environment on the hot-corrosion behavior of Ni in the temperature range 750-950 C has been studied. Below the melting point of Na2SO4 (884 C), rapid corrosion takes place by formation of a Na2SO4-NiSO4 melt which can penetrate the porous oxide scale and give rise to sulfide information by coming in contact with the metal. The distribution of the sulfides depends on the SO2 level in the ambient gas. Continued corrosion occurs by a sulfidation-oxidation mechanism. At temperatures above the melting point of Na2SO4, accelerated degradation occurs via dissolution of the surface scale, followed by reprecipitation of the oxide in a nonprotective form.

Misra, A. K.↗
NASA NTRS1977

The effect of NaCl/g/ on the Na2SO4-induced hot corrosion of NiAl

Studies have been performed to examine the effect of NaCl vapor on the Na2SO4-induced hot corrosion of the alumina former NiAl. In the incubation period associated with such hot corrosion, NaCl(g) has been shown to be effective in removing aluminum from below the protective alumina scale and redepositing it as Al2O3 whiskers on the surface of the Na2SO4-coated sample. Similar effects seen in simple oxidation are associated with isothermal rupturing of the protective alumina scale.

Smeggil, J. G.↗
NASA NTRS1984

Deposition of Na2SO4 from salt-seeded combustion gases of a high velocity burner rig

The mechanism of deposition of Na2SO4 was studied under controlled laboratory conditions and the results have been compared to a recently developed comprehensive theory of vapor deposition. Thus Na2SO4, NaCl, NaNO3 and simulated sea salt solutions were injected into the combustor of a nominal Mach 0.3 burner rig burning jet fuel at constant fuel/air ratios. The deposits formed on inert collectors, rotation in the cross flow of the combustion gases, were weighed and analyzed. Collector temperature was uniform and could be varied over a large range by internal air cooling. Deposition rates and dew point temperatures were determined. Supplemental testing included droplet size measurements of the atomized salt solutions. These tests along with thermodynamic and transport calculations were utilized in the interpretation of the deposition results.

Santoro, G. J.↗
NASA NTRS1986

Mechanism of Na2SO4-induced corrosion of molybdenum containing nickel-base superalloys at high temperatures. I - Corrosion in atmospheres containing O2 only. II - Corrosion in O2 + SO2 atmospheres

Kinetics of the Na2SO4-induced corrosion of the molybdenum-containing nickel-base superalloys, B-1900 and Udimet 700, coated with Na2MoO4, has been studied in oxygen atmosphere at temperatures ranging from 750 to 950 C. Because the gas turbine atmosphere always contains some SO2 and SO3, the effect of atmospheric SO2 content on corrosion of Udimet-700 has also been studied. It was found that in the O2 atmosphere the melt in the catastrophic corrosion phase consists of Na2MoO4 plus MoO3, with the onset of the catastrophic corrosion coinciding with the appearance of MoO3. In the presence of low levels of atmospheric SO2 (below 0.24 percent), the melt during catastrophic corrosion contains, in addition to Na2MoO4 and MoO3, some quantities of Na2SO4. At the levels of SO2 above 1 percent, no catastrophic corrosion was observed. At these SO2 levels, internal sulfidation appears to be the primary mode of degradation.

Misra, A. K.↗
DOE OSTI2020

Materials Data on Na2SO4 by Materials Project

Na2SO4 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.33 Å. In the second Na1+ site, Na1+ is bonded to twelve O2- atoms to form edge-sharing NaO12 cuboctahedra. There are six shorter (2.61 Å) and six longer (2.90 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three equivalent O2- atoms. All Na–O bond lengths are 2.17 Å. S6+ is bonded in a single-bond geometry to one O2- atom. The S–O bond length is 1.45 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three Na1+ atoms. In the second O2- site, O2- is bonded in a single-bond geometry to three equivalent Na1+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2SO4 by Materials Project

Na2SO4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.87 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent SO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are two shorter (2.36 Å) and four longer (2.45 Å) Na–O bond lengths. S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 41–49°. There is two shorter (1.48 Å) and two longer (1.50 Å) S–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and one S6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2SO4 by Materials Project

Na2SO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent SO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.31–2.56 Å. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.41–3.02 Å. S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 41–51°. There is two shorter (1.49 Å) and two longer (1.50 Å) S–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one S6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one S6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2SO4 by Materials Project

Na2SO4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted trigonal bipyramidal geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.70 Å. In the second Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.23–2.86 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.81 Å. In the fourth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–3.01 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of S–O bond distances ranging from 1.52–1.56 Å. In the second S6+ site, S6+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.52 Å) and two longer (1.54 Å) S–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one S6+ atom. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Na1+ and one O2- atom. The O–O bond length is 1.27 Å. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to two Na1+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three Na1+ and one S6+ atom. In the fifth O2- site, O2- is bonded to three Na1+ and one S6+ atom to form corner-sharing ONa3S tetrahedra. In the sixth O2- site, O2- is bonded to three Na1+ and one S6+ atom to form distorted corner-sharing ONa3S tetrahedra. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Na1+ and one S6+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Na1+ and one O2- atom.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Theoretical and experimental studies of the deposition of Na2So4 from seeded combustion gases

Flames in a Mach 0.3 atmospheric pressure laboratory burner rig were doped with sea salt, NaS04, and NaCl, respectively, in an effort to validate theoretical dew point predictions made by a local thermochemical equilibrium (LTCE) method of predicting condensation temperatures of sodium sulfate in flame environments. Deposits were collected on cylindrical platinum targets placed in the combustion products, and the deposition was studied as a function of collector temperature. Experimental deposition onset temperatures checked within experimental error with LTCE-predicted temperatures. A multicomponent mass transfer equation was developed to predict the rate of deposition of Na2SO4(c) via vapor transport at temperatures below the deposition onset temperature. Agreement between maximum deposition rates predicted by this chemically frozen boundary layer (CFBL) theory and those obtained in the seeded laboratory burner experiments is good.

Kohl, F. J.↗
NASA NTRS1977

Theoretical and experimental studies of the deposition of Na2SO4 from seeded combustion gases

A basic point in the hot corrosion of turbine components is the deposition of sodium sulfate from flames containing sodium and sulfur. An experimental study is described which examines a dew point prediction theory based on the local thermochemical equilibrium (LTCE) method, and a means to calculate the deposition rate is suggested. In addition, a convective diffusion theory, based on the assumption of a chemically frozen boundary layer, utilizing the LTCE results, and imposing the additional effects of mass transport, was also successful in predicting dew points for Na2SO4-seeded combustion gases. A multicomponent mass transfer equation was derived to predict NaSO4 deposition rate via vapor transport at temperatures below the deposition onset temperature.

Kohl, F. J.↗
NASA NTRS1977

Formation of Na2SO4 and K2SO4 in flames doped with sulfur and alkali chlorides and carbonates

High pressure, free-jet expansion, mass spectrometric sampling was used to identify directly and to measure reaction products formed in doped methane-oxygen flames. Flames were doped with SO2 or CH3SH and sodium or potassium chlorides or carbonates. Gaseous NA2SO4 or K2S04 molecules were formed in residence times on the order of msec for each combination of dopants used. Composition profiles of combustion products were measured and compared with equilibrium thermodynamic calculations of product composition.

Fryburg, G. C.↗
NASA NTRS1977

Formation of Na2SO4 and K2SO4 in flames doped with sulfur and alkali chlorides and carbonates

High pressure, free-jet expansion, mass spectrometric sampling was used to identify directly and to measure reaction products formed in doped methane-oxygen flames. Flames were doped with SO2 or CH3SH and sodium or potassium chlorides or carbonates. Gaseous Na2SO4 or K2SO4 molecules were formed in residence times on the order of 1 msec for each combination of dopants used. Composition profiles of combustion products were measured and compared with equilibrium thermodynamic calculations of product composition.

Fryburg, G. C.↗
NASA NTRS1987

Role of molybdenum in the Na2SO4 induced corrosion of superalloys at high temperature

Sodium sulfate induced corrosion of a molybdenum containing nickel-base superalloy, Udimet 700, was studied in laboratory furnace test and in a high velocity (Mach 0.3) burner rig. Tlhe effect of SO2 content in the atmosphere on the corrosion behavior in the laboratory furnace tests was determined. catastrophic corrosion occursonly when the melt contains MoO3 in addition to Na2SO4 and Na2MoO4. The conditions under which catastrophic corrosion occurs are identified and a mechanism is described to explain the catastrophic corrosion.

Misra, A. K.↗
NASA NTRS1985

Deposition of Na2SO4 from salt-seeded combustion gases of a high velocity burner rig

With a view to developing simulation criteria for the laboratory testing of high-temperature materials for gas turbine engines, the deposition rates of sodium sulfate from sodium salt-seeded combustion gases were determined experimentally using a well instrumented high-velocity burner. In the experiments, Na2SO4, NaCl, NaNO3, and simulated sea salt solutions were injected into the combustor of the Mach 0.3 burner rig operating at constant fuel/air ratios. The deposits formed on an inert rotating collector were then weighed and analyzed. The experimental results are compared to Rosner's vapor diffusion theory. Some additional test results, including droplet size distribution of an atomized salt spray, are used in interpreting the deposition rate data.

Santoro, G. J.↗
DOE OSTI2021

A microstructural investigation of a Na2SO4 activated cement-slag blend

The reactivity and early strength of cement:slag binders is usefully enhanced by the addition of sodium sulfate though the underlying mechanisms of the relationship between the enhanced hydration reactions and the structural aspects of the strength behavior remain unclear. In this study, microstructural development in the presence of Na{sub 2}SO{sub 4} was investigated utilizing mercury intrusion porosimetry (MIP), NMR relaxometry, and XRD. Increased rates of early strength development and decreased rates of late strength development due to the presence of added Na{sub 2}SO{sub 4} were linked to effects on capillary porosity refinement. While degree of hydration at later age was shown to have been lower in the presence of Na{sub 2}SO{sub 4}, and may have been responsible for the higher capillary porosity, a clear alteration in the pathway of microstructural development had occurred with inhibition to hydration of the slag component due to earlier microstructural development proposed.

36 MATERIALS SCIENCE↗