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Cited by 14Thermal properties of materialsSuperconducting Materials and ApplicationsThermodynamic and Structural Properties of Metals and Alloys

THERMAL AND ELECTRICAL CONDUCTIVITY MEASUREMENTS OF CDA 510 PHOSPHOR BRONZE

Open access
Tuttle, J., Canavan, E., DiPirro, M., Balachandran, U. (Balu)·2010·AIP Conference Proceedings
DOI 10.1063/1.3402333
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Abstract

Many cryogenic systems use electrical cables containing phosphor bronze wire. While phosphor bronze’s electrical and thermal conductivity values have been published, results vary among different phosphor bronze formulations. The James Webb Space Telescope (JWST) will use several phosphor bronze wire harnesses containing a specific formulation (CDA 510, annealed temper). These harnesses dominate the heat conducted into the JWST instrument stage, and approximately half of the harness conductance is due to the phosphor bronze wires. Since the JWST radiators are expected to keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used. We describe an experiment that measured its electrical and thermal conductivity between 4 and 295 Kelvin.

AI snapshot

Written from the paper’s full text.

TL;DR

This paper measures electrical resistivity and thermal conductivity of CDA 510 phosphor bronze wire from JWST cabling between 4 and 295 K and compares the results to Wiedemann-Franz expectations and other alloys. It finds low-temperature ρ ≈ 88 nΩ·m, RRR = 1.24, a thermal conductivity fit accurate to better than 0.6%, and that phosphor bronze can outperform Hastelloy in current-carrying cryogenic wires but is still worse than optimized copper.

Key findings

  • The measured electrical resistivity has a temperature-independent low-temperature value of about 88 nΩ·m, a near-linear weak temperature dependence above 40 K, and a residual resistance ratio RRR = R300K/R4.2K = 1.24.
  • The thermal conductivity data were fit to a polynomial in ln(T); the fit matches all data points to better than 0.6 percent. Preliminary data taken without the guard can and insulation show that guard and insulation are necessary for accurate measurements above about 40 K.
  • The Wiedemann-Franz law does not describe the material well: L/L0 is always greater than 1 over the studied range because κ includes a significant phonon contribution.
  • For an optimized 50 cm wire carrying 1 A with the cold end at 4 K, a 20-to-4 K Hastelloy wire delivers almost four times more heat than ideal copper, while phosphor bronze is about 50% worse than copper; for a 300-to-4 K wire, Hastelloy and phosphor bronze deliver about two times and 20% more heat than copper, respectively.

Methods

  • Electrical resistivity was measured on an 848 mm long, 0.249 mm diameter CDA 510 phosphor bronze wire coiled on a cryostat base plate, using a Picowatt AVS-47 resistance bridge at controlled temperatures between 4 and 300 K; uncertainty was less than ±1%, with systematic geometry error at worst ±1%.
  • Thermal conductivity was measured on 10 parallel 76-mm-long phosphor bronze wires from the same JWST cable, with copper strip heat sinks, Cernox thermometers, a heater, a guard can, and Fiberfrax insulation; steady-state power versus ΔT was measured at four temperature gradients and fit by linear regression.
  • A simple iterative thermal model with ten nodes, ignoring radiation, was used to optimize 50 cm long wires carrying 1 A with the cold end held at 4 K, using curve fits for Hastelloy, phosphor bronze, and 26% drawn copper.

Limitations

  • The paper states that the authors were unable to find data on the effects of annealing or work hardening phosphor bronze, and it is not clear that the wire remained in the vendor-indicated annealed state after insulation and packaging into twisted pairs.
  • The paper states that preliminary measurements without the guard can and insulation show those components are necessary for accurate thermal conductivity measurements above about 40 K.
  • The text makes evident that CDA-510 allows a range of tin and phosphorous contents, and cited work indicates such ranges can produce a factor of two change in ρ and about a 35% change in κ, so results from this single cable sample may not represent all CDA 510 phosphor bronze.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1063/1.3402333

Cites

4 of 4 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 17 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Over the studied temperature range, the Lorenz ratio L/L0 for CDA 510 phosphor bronze is always greater than 1 due to the contribution of phonon thermal conductivity κG.

    “Over the studied temperature range L/L 0 is always greater than 1 due to the contribution of κ G .”
    Quote in the paperSubstantial claim
  • Findingown data

    Above 40 Kelvin, the measured electrical resistivity of CDA 510 phosphor bronze shows a near linear weak temperature dependence.

    “Above 40 Kelvin ρ shows a near linear weak temperature dependence.”
    Quote in the paperNot a substantial claim
  • Findingown data

    For a wire running from 300 to 4 Kelvin, an optimized Hastelloy wire delivers about two times more heat than an ideal copper wire.

    “If the wire runs from 300 to 4 Kelvin, the Hastelloy and phosphor bronze deliver about two times and 20% more heat than copper, respectively.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The residual resistance ratio RRR = R300K/R4.2K for the measured CDA 510 phosphor bronze wire is 1.24.

    “The residual resistance ratio RRR = R 300K /R 4.2K is 1.24.”
    Quote in the paperNot a substantial claim
  • Findingown data

    For a current lead running from 20 to 4 Kelvin, an optimized Hastelloy wire delivers almost four times more heat than an ideal copper wire.

    “For a current lead running from 20 to 4 Kelvin, an optimized Hastelloy wire delivers almost four times more heat than an ideal copper wire.”
    Quote in the paperSubstantial claim
  • May combine two claims. 13
  • The quote only partly states this claim. 2
  • Classified as probably not a substantial claim. 11

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    The measured thermal conductivity of CDA 510 phosphor bronze as a function of temperature is fit by an 8th-order polynomial in ln(T) that matches all data points to better than 0.6 percent with no systematic deviations.

    “The residuals indicate no systematic deviations from the data, and the fit matches all data points to better than 0.6 percent.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The measured thermal conductivity of CDA 510 phosphor bronze agrees well with data from Zavaritskii and Zeldovich below 25 Kelvin, but at higher temperatures the literature data are systematically lower than the present measurements.

    “These data agree well our own below 25 Kelvin, but at higher temperatures they are systematically lower than ours.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [7]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • The quote only partly states this claim.

    Findingown data

    The measured electrical resistivity of CDA 510 phosphor bronze wire from JWST cabling has a temperature-independent value of about 88 nΩ·m at low temperatures.

    “At low temperatures it has a temperature-independent value of about 88 nΩ•m.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).

    Findingnone given

    For a current lead running from 20 to 4 Kelvin, an optimized phosphor bronze wire delivers about 50% more heat than an ideal copper wire.

    “Phosphor bronze fares better than Hastelloy but is still about 50% worse than copper.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The relationship between thermal conductivity and electrical resistivity for CDA 510 phosphor bronze is not very well described by the Wiedemann-Franz law, because κ includes a significant contribution from phonons.

    “The relationship between these parameters is not very well described by the Wiedemann-Franz law, since κ includes a significant contribution from phonons.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For pure aluminum samples with RRR = 100, thermal conductivity can be as low as half the Wiedemann-Franz predicted value at 100 Kelvin.

    “The thermal conductivity of pure aluminum samples (RRR = 100) can be as low as half the predicted value at 100 Kelvin [6].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For annealed pure copper (RRR = 1600), thermal conductivity is as low as one-third the Wiedemann-Franz prediction at about 25 Kelvin.

    “For annealed pure copper (RRR = 1600), κ is as low as one-third the prediction at about 25 Kelvin [10].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Raising either the tin or phosphorous content increased electrical resistivity ρ and lowered thermal conductivity κ in phosphor bronze alloys.

    “Raising either the tin or phosphorous content increased ρ and lowered κ.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [2]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The Wiedemann-Franz law breaks down at intermediate temperatures where electron scattering is not entirely elastic, reducing κ below the Wiedemann-Franz prediction for a given ρ.

    “The law breaks down at intermediate temperatures where the electron scattering is not entirely elastic, reducing κ to below the Wiedemann-Franz prediction for a given ρ [8,9].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [8]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [9]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    The thermal conductivity of the fibrous insulation material (Fiberfrax) is proportional to T^3 and is much lower than phosphor bronze's κ, even at room temperature.

    “The measured thermal conductivity of this material is proportional to T 3 and was much lower than phosphor bronze's κ, even at room temperature [4].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    The CDA-510 phosphor bronze specification allows 4.2-5.8% tin and 0.03-0.35% phosphorous.

    “To reduce this uncertainty vendors use a standard specification known as CDA-510 phosphor bronze, which allows 4.2 -5.8% tin and 0.03 -0.35% phosphorous [1].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Varying the tin content over its entire CDA-510-allowed range resulted in a factor of two change in electrical resistivity ρ and about a 35% change in thermal conductivity κ.

    “Varying the tin content over its entire CDA-510-allowed range resulted in a factor of two change in ρ and about a 35% κ change [2].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [2]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Hastelloy, which is 40% more resistive at low temperatures than the phosphor bronze sample, has a 5 Kelvin Lorenz ratio of about 12, which monotonically decreases to about 2.6 at room temperature.

    “Hastelloy, which is 40% more resistive at low temperatures than our sample, has a 5 Kelvin Lorenz ratio of about 12, which monotonically decreases to about 2.6 at room temperature [5].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For pure copper cold-drawn to 26% of its original cross-sectional area (RRR = 130), thermal conductivity dips to as low as 50% of the Wiedemann-Franz prediction at about 45 Kelvin.

    “For pure copper cold-drawn to 26% of its original cross sectional area (RRR = 130), κ also dips to as low as 50% of the prediction, but at about 45 Kelvin.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The L/L0 curve for aluminum 2024-T4 has a low-temperature value less than 1.1 and a minimum below 1.0 near 100 Kelvin.

    “The L/L 0 curve for aluminum 2024-T4, with a low temperature ρ only about one third that of our phosphor bronze sample, has a low temperature value less than 1.1 and a minimum below 1.0 near 100 Kelvin [6].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Hastelloy has a low-temperature electrical resistivity of 122 nΩ·m and a residual resistance ratio RRR of 1.03.

    “In comparison, Hastelloy has a low-temperature ρ of 122 nΩm and a RRR value of 1.03 [5].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductnone given

    Random error in power measurement was somewhat larger, but well below 1%.

    “Random error in the power measurement was somewhat larger, but well below 1%.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The variation in electrical resistivity ρ with tin content was much greater at 4.2 Kelvin than at 300 Kelvin, while the effect on thermal conductivity κ was greater at the high temperature end of the range.

    “The variation in ρ was much greater at 4.2 Kelvin than at 300 Kelvin, while the effect on κ was greater at the high temperature end of the range.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    The Wiedemann-Franz law over-predicts thermal conductivity over a wide temperature range for pure metals and generally under-predicts thermal conductivity everywhere for alloys.

    “This is a risky approach, however, as it over-predicts κ over a wide temperature range for pure metals and generally underpredicts κ everywhere for alloys.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In alloys where electron conduction is strongly suppressed by scattering, phonon thermal conductivity κG can be as high or higher than electronic thermal conductivity κE.

    “In alloys, where electron conduction is strongly suppressed by scattering, κ G can be as high or higher than κ E [11].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For high-resistivity alloys such as Hastelloy, phonon thermal conductivity κG is much greater than electronic thermal conductivity κE.

    “For high-resistivity alloys, such as Hastelloy, κ G >> κ E [5].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

21 of 21

  • The paper relies on this without support.

    The JWST instrument stage is radiatively cooled to about 40 Kelvin and has limited cooling margin.

    “Since the JWST radiators are expected to keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used.”

  • The paper relies on this without support.

    The JWST phosphor bronze wire harnesses dominate the heat conducted into the JWST instrument stage.

    “These harnesses dominate the heat conducted into the JWST instrument stage, and approximately half of the harness conductance is due to the phosphor bronze wires.”

  • The paper relies on this without support.

    Approximately half of the harness conductance is due to the phosphor bronze wires.

    “These harnesses dominate the heat conducted into the JWST instrument stage, and approximately half of the harness conductance is due to the phosphor bronze wires.”

  • The paper relies on this without support.

    The wire extracted from the JWST cable is CDA 510 phosphor bronze.

    “We measured the electrical resistance of an 848 mm long sample of 0.249 mm diameter phosphor bronze CDA 510 wire, which was coiled around and taped to our thermal conductivity rig's base plate, inside a cryostat cooled by a Gifford-McMahon cryocooler.”

  • The paper relies on this without support.

    Thermal conduction through phosphor bronze wires represents a large fraction of the total heat conduction in the JWST harnesses.

    “In fact, thermal conduction through phosphor bronze wires represents a large fraction of the total heat conduction.”

  • The paper relies on this without support.

    The heat conducted by the JWST harnesses represents a large fraction of the total parasitic heat load into the instrument stage.

    “The heat conducted by these harnesses represents a large fraction of the total parasitic heat load into the stage.”
6 of 6

Cites

Flagged first, then by citations

2 of the 6 references couldn’t be matched to a known paper.

Research works printed but not linked: 7

  1. Kosaka, K., Yamanaka, N., Matsukawa, M., and Yoshizawa, M., J. of JCBRA, 39, pp. 197-201 (2006).
  2. Moore, J. P., Williams, R. K., and Graves, R. S., Rev. of Sci. Instr., 45(1), pp. 87-95 (1973).
  3. Lu, J., Choi, E. S., and Zhou, H. D., J. Appl. Phys., 103 pp. 064908-1-6 (2008).
  4. Powell, R. L., Hall, W. J., and Roder, H. M., J. Appl. Phys., 31 pp. 496 -503 (1960).
  5. Zavaritskii, N.V. and Zeldovich, A.G., Sov. Phys. -Tech. Phys. 1 pp. 1970-1974 (1956).
  6. Ashcroft, N. and Merman, N. D., Solid State Physics, Saunders, Philadelphia, 1976.
  7. Powell, R. L., Roder, H. M., and Hall, W. J., Phys. Rev., 115 pp. 314-323, (1959).

Cited by

Sorted by citations

Related

Authors
Tuttle, J., Canavan, E., DiPirro, M., & Balachandran, U. (.
Affiliations
Goddard Space Flight Center (US)
ORCID
DiPirro, M.
Venue
AIP Conference Proceedings
Publisher
AIP
Published
2010
Pages
55-62
ISSN
0094-243X (ISSN-L)
DOI
10.1063/1.3402333
OpenAlex
W2037034463
Semantic Scholar
0694461f806728a143f9e4360e0885bbe00033b3
Cited by
14
References
6
Citations by year
2026: 2 · 2025: 1 · 2024: 2 · 2020: 2 · 2018: 1 · 2017: 1 · 2015: 2 · 2013: 1 · 2012: 2
FWCI
5.12
Type
conference paper
Language
en
Open access
Locations
  • AIP conference proceedings (publishedVersion)
  • NASA STI Repository (National Aeronautics and Space Administration) (submittedVersion)
Funders
National Aeronautics and Space Administration
Topics
  • Physical Sciences › Materials Science › Materials Chemistry › Thermal properties of materials
  • Physical Sciences › Engineering › Biomedical Engineering › Superconducting Materials and Applications
  • Physical Sciences › Engineering › Mechanical Engineering › Thermodynamic and Structural Properties of Metals and Alloys
Keywords
phosphor bronze, thermal conductivity, electrical conductivity, cryogenic cables, wiring harness, James Webb Space Telescope, heat conduction, low-temperature conductivity

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