High-temperature thermodynamical studies by a mass spectrometry device for measurements using multiple effusion cells

Chatillon, C.; Senillou, C.; Allibert, M.; Pattoret, A.

doi:10.1063/1.1134618

Cited by 45 publications

(33 citation statements)

References 4 publications

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“…In theory, thermodynamic activities can be measured directly, by substituting Eq 2 into Eq 1, according to Eq 3. [13][14][15][16][17] aðiÞ ¼…”

Section: Activity Measurementsmentioning

confidence: 99%

“…[16,17] Consistent molecular beam sampling was achieved by inserting two fixed apertures (a ''field aperture'', 0.8 mm in diameter, and a ''source aperture'', 2 mm in diameter about 38 mm apart) between the effusion cell and ion source and accurate alignment of each effusion-cell orifice with the fixed apertures. [14][15][16][17] The apertures fix the shape and position of the molecular beam, which defines an ionization volume that is independent of the vapor source. This configuration works best when the fixed apertures define a source area for the molecular beam, A s , that is smaller than the cross section of the effusion orifice, A o , a condition referred to as ''restricted collimation''.…”

Section: Activity Measurementsmentioning

confidence: 99%

“…These activities were measured directly by the vapor pressure technique with a multiple effusion-cell vapor source coupled to a mass spectrometer (multi-cell KEMS). [12][13][14][15][16][17] The measurement procedure for the Ni-Al-Pt system was developed with several b-(Ni,Pt)Al compositions and [Al(l) + Al 2 O 3 (s)] and [Ni(s,l) + Al 2 O 3 (s)] were used as reference states for Al and Ni, respectively. [17] The details of incorporating the thermodynamic properties of these reference states are described in the experimental procedure section.…”

Section: Introductionmentioning

confidence: 99%

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Partial Thermodynamic Properties of γ′-(Ni,Pt)3Al in the Ni-Al-Pt system

Copland

2007

J Phs Eqil and Diff

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Measurements were made to determine how Pt influences the partial thermodynamic properties of Al and Ni in c¢-(Ni,Pt) 3 Al and liquid in the Ni-Al-Pt system. The activities of Al and Ni were measured with a multiple effusion-cell mass spectrometer (multi-cell KEMS). For a constant X Al = 0.24, adding Pt, from X Pt = 0.02-0.25, reduces a(Al) almost an order of magnitude, from 2 · 10 )4 to 2 · 10 )5 , at 1560 K. This occurred for D m " H(Al) of )203 ± 10 kJ mol )1 and the a(Al) decrease was due to D m " S(Al) increasing from )60 to )40 J mol )1 K )1 with Pt addition. The large negative D m " H(Al) and D m " S(Al) indicate Al-atoms are highly ordered in c¢-(Ni,Pt) 3 Al. Nickel activity, a(Ni), remained essentially constant,~0.7, indicating an increasing ternary interaction between Ni-atoms and (Al + Pt)-atoms with Pt addition, where c Ni increased from about 0.7 to 1.2. This is supported by D m " H(Ni) in the range 6.1-7.1 ± 1.5 kJ mol )1 at 1520 K, and a positive D m " S xs (Ni), which suggest disorder on the Ni-lattice. For a consistent X Al = 0.27, adding Pt, from X Pt = 0.10-0.25, also reduces a(Al) but only by a factor of about 3, while a(Ni) remained essentially constant, with c Ni increasing from about 0.7 to 0.95. A dramatic change in the mixing behavior was observed between the X Al ¼ 0:24 and 0.27 series of alloys, where D m " H(Al) and D m " S(Al) are seen to increase about 50 kJ mol )1 and 20 J mol )1 K )1 at T = 1566 K, respectively. In contrast, D m " H(Ni) decreased about 16 kJ mol )1 at T = 1520 K and D m " S xs (Ni) changed from a positive to a negative value.

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“…In theory, thermodynamic activities can be measured directly, by substituting Eq 2 into Eq 1, according to Eq 3. [13][14][15][16][17] aðiÞ ¼…”

Section: Activity Measurementsmentioning

confidence: 99%

Section: Activity Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Partial Thermodynamic Properties of γ′-(Ni,Pt)3Al in the Ni-Al-Pt system

Copland

2007

J Phs Eqil and Diff

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“…In an attempt to obtain easier measurements, a double Knudsen cell mass spectrometer was developed [29][30][31] (Fig. 5).…”

Section: A X Amentioning

confidence: 99%

Thermodynamic Measurements of Alloys and Compounds by Double Knudsen Cell Mass Spectrometry and Their Application to Materials Processing

et al. 2014

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For the development and optimization of materials processing a collection of thermodynamic information concerning substances that participate in the reactions is important. One fundamental way to obtain such information is to measure the vapor pressure of gas species under conditions where they are in equilibrium with the condensed phases. Over the past 60 years Knudsen cell mass spectrometry has been used to identify and quantitatively determine gas species at high temperatures. is article describes thermodynamic foundation and examples of measurements in order to demonstrate the use of mass spectrometry focusing on the eld of process metallurgy and recycling processes.

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“…The partial pressures were determined as a function of temperature by Knudsen effusion-cell mass spectrometry, KEMS, where p(i) inside the effusion-cell is determined from the measured intensity of a representative ion beam, I i , and absolute temperature, T, according to the relationship: p(i) = I i T / S i (where S i is the instrument sensitivity factor) [38] . The need to determine S i and absolute partial pressure was removed in this study with a multiple effusion-cell vapor source (with three effusion-cells), multi-cell KEMS, which allows the relative partial pressure between samples in adjacent effusion-cells to be determined directly [39][40][41][42] .…”

Section: Alloy and Sample Preparationmentioning

confidence: 99%

Formation of γ'-Ni3Al via the Peritectiod Reaction: γ + � (+ Al2O3) = γ' (+ Al2O3)

Copland¹

2008

Superalloys 2008 (Eleventh International Symposium)

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The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8 -32 at.%Al and temperature range T = 1400 − 1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of γ′-Ni 3 Al-containing alloys occurs by the eutectic reaction, L (+ Al 2 O 3 ) = γ + β (+ Al 2 O 3 ), at 1640 ± 1 K and a liquid composition of 24.8 ± 0.2 at.%Al (at an unknown oxygen content). The {γ + β + Al 2 O 3 } phase field is stable over the temperature range 1633 − 1640 K, and γ′-Ni 3 Al forms via the peritectiod, γ + β (+ Al 2 O 3 ) = γ′ (+ Al 2 O 3 ), at 1633 ± 1 K. This behavior is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steadystate solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the γ′-Ni 3 Al phase field.

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High-temperature thermodynamical studies by a mass spectrometry device for measurements using multiple effusion cells

Cited by 45 publications

References 4 publications

Partial Thermodynamic Properties of γ′-(Ni,Pt)3Al in the Ni-Al-Pt system

Partial Thermodynamic Properties of γ′-(Ni,Pt)3Al in the Ni-Al-Pt system

Thermodynamic Measurements of Alloys and Compounds by Double Knudsen Cell Mass Spectrometry and Their Application to Materials Processing

Formation of γ'-Ni<sub>3</sub>Al via the Peritectiod Reaction: γ + � (+ Al<sub>2</sub>O<sub>3</sub>) = γ' (+ Al<sub>2</sub>O<sub>3</sub>)

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High-temperature thermodynamical studies by a mass spectrometry device for measurements using multiple effusion cells

Cited by 45 publications

References 4 publications

Partial Thermodynamic Properties of γ′-(Ni,Pt)3Al in the Ni-Al-Pt system

Partial Thermodynamic Properties of γ′-(Ni,Pt)3Al in the Ni-Al-Pt system

Thermodynamic Measurements of Alloys and Compounds by Double Knudsen Cell Mass Spectrometry and Their Application to Materials Processing

Formation of &#947;'-Ni<sub>3</sub>Al via the Peritectiod Reaction: &#947; + � (+ Al<sub>2</sub>O<sub>3</sub>) = &#947;' (+ Al<sub>2</sub>O<sub>3</sub>)

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Formation of γ'-Ni<sub>3</sub>Al via the Peritectiod Reaction: γ + � (+ Al<sub>2</sub>O<sub>3</sub>) = γ' (+ Al<sub>2</sub>O<sub>3</sub>)