Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature

Matthias T. Agne, Kazuki Imasato, Shashwat Anand, Kathleen Lee, Sabah K. Bux, Alex Zevalkink, Alexander J.E. Rettie, Duck Young Chung, Mercouri G Kanatzidis, G. Jeffrey Snyder

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The thermoelectric figure of merit reported for n-type Mg 3 (Sb,Bi) 2 compounds has made these materials of great engineering significance, increasing the need for accurate evaluations of their thermal conductivity. Thermal conductivity is typically derived from measurements of thermal diffusivity and determination of the specific heat capacity. The uncertainty in this method (often 10% or more) is frequently attributed to measurement of heat capacity such that estimated values are often more accurate. Inconsistencies between reported thermal conductivity of Mg 3 (Sb,Bi) 2 compounds may be attributed to the different values of heat capacity measured or used to calculate thermal conductivity. The high anharmonicity of these materials can lead to significant deviations at high temperatures from the Dulong-Petit heat capacity, which is often a reasonable substitute for measurements at high temperatures. Herein, a physics-based model is used to assess the magnitude of the heat capacity over the entire temperature range up to 800 K. The model agrees in magnitude with experimental low-temperature values and reproduces the linear slope observed in high-temperature data. Owing to the large scatter in experimental values of high-temperature heat capacity, the model is likely more accurate (within ±3%) than a measurement of a new sample even for doped or alloyed materials. It is found that heat capacity for the solid solution series can be simply described (for temperatures: 200K≤T≤800K) by the polynomial equation: c p [Jg −1 K −1 ]=[Formula presented](1+1.3×10 −4 T−4×10 3 T −2 ),where 3NR=124.71Jmol −1 K −1 , M W is the molecular weight [gmol −1 ] of the formula unit being considered, and T is temperature in K. This heat capacity is recommended to be a standard value for reporting and comparing the thermal conductivity of Mg 3 (Sb,Bi) 2 including doped or alloyed derivatives. A general form of the equation is given which can be used for other material systems.

Original languageEnglish
Pages (from-to)83-88
Number of pages6
JournalMaterials Today Physics
Volume6
DOIs
Publication statusPublished - Aug 1 2018

Fingerprint

Specific heat
specific heat
Thermal conductivity
thermal conductivity
Temperature
Thermal diffusivity
thermal diffusivity
figure of merit
temperature
Solid solutions
molecular weight
polynomials
solid solutions
Physics
Molecular weight
Polynomials
engineering
substitutes
slopes
Derivatives

Keywords

  • Heat capacity
  • Mg Bi
  • Mg Sb
  • Thermal conductivity
  • Thermoelectric

ASJC Scopus subject areas

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)
  • Energy (miscellaneous)

Cite this

Agne, M. T., Imasato, K., Anand, S., Lee, K., Bux, S. K., Zevalkink, A., ... Snyder, G. J. (2018). Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature Materials Today Physics, 6, 83-88. https://doi.org/10.1016/j.mtphys.2018.10.001

Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature . / Agne, Matthias T.; Imasato, Kazuki; Anand, Shashwat; Lee, Kathleen; Bux, Sabah K.; Zevalkink, Alex; Rettie, Alexander J.E.; Chung, Duck Young; Kanatzidis, Mercouri G; Snyder, G. Jeffrey.

In: Materials Today Physics, Vol. 6, 01.08.2018, p. 83-88.

Research output: Contribution to journalArticle

Agne, MT, Imasato, K, Anand, S, Lee, K, Bux, SK, Zevalkink, A, Rettie, AJE, Chung, DY, Kanatzidis, MG & Snyder, GJ 2018, ' Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature ', Materials Today Physics, vol. 6, pp. 83-88. https://doi.org/10.1016/j.mtphys.2018.10.001
Agne, Matthias T. ; Imasato, Kazuki ; Anand, Shashwat ; Lee, Kathleen ; Bux, Sabah K. ; Zevalkink, Alex ; Rettie, Alexander J.E. ; Chung, Duck Young ; Kanatzidis, Mercouri G ; Snyder, G. Jeffrey. / Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature In: Materials Today Physics. 2018 ; Vol. 6. pp. 83-88.
@article{e1a0d9261682405ab5476a0297db2e2d,
title = "Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature",
abstract = "The thermoelectric figure of merit reported for n-type Mg 3 (Sb,Bi) 2 compounds has made these materials of great engineering significance, increasing the need for accurate evaluations of their thermal conductivity. Thermal conductivity is typically derived from measurements of thermal diffusivity and determination of the specific heat capacity. The uncertainty in this method (often 10{\%} or more) is frequently attributed to measurement of heat capacity such that estimated values are often more accurate. Inconsistencies between reported thermal conductivity of Mg 3 (Sb,Bi) 2 compounds may be attributed to the different values of heat capacity measured or used to calculate thermal conductivity. The high anharmonicity of these materials can lead to significant deviations at high temperatures from the Dulong-Petit heat capacity, which is often a reasonable substitute for measurements at high temperatures. Herein, a physics-based model is used to assess the magnitude of the heat capacity over the entire temperature range up to 800 K. The model agrees in magnitude with experimental low-temperature values and reproduces the linear slope observed in high-temperature data. Owing to the large scatter in experimental values of high-temperature heat capacity, the model is likely more accurate (within ±3{\%}) than a measurement of a new sample even for doped or alloyed materials. It is found that heat capacity for the solid solution series can be simply described (for temperatures: 200K≤T≤800K) by the polynomial equation: c p [Jg −1 K −1 ]=[Formula presented](1+1.3×10 −4 T−4×10 3 T −2 ),where 3NR=124.71Jmol −1 K −1 , M W is the molecular weight [gmol −1 ] of the formula unit being considered, and T is temperature in K. This heat capacity is recommended to be a standard value for reporting and comparing the thermal conductivity of Mg 3 (Sb,Bi) 2 including doped or alloyed derivatives. A general form of the equation is given which can be used for other material systems.",
keywords = "Heat capacity, Mg Bi, Mg Sb, Thermal conductivity, Thermoelectric",
author = "Agne, {Matthias T.} and Kazuki Imasato and Shashwat Anand and Kathleen Lee and Bux, {Sabah K.} and Alex Zevalkink and Rettie, {Alexander J.E.} and Chung, {Duck Young} and Kanatzidis, {Mercouri G} and Snyder, {G. Jeffrey}",
year = "2018",
month = "8",
day = "1",
doi = "10.1016/j.mtphys.2018.10.001",
language = "English",
volume = "6",
pages = "83--88",
journal = "Materials Today Physics",
issn = "2542-5293",
publisher = "Elsevier Ltd",

}

TY - JOUR

T1 - Heat capacity of Mg 3 Sb 2 , Mg 3 Bi 2 , and their alloys at high temperature

AU - Agne, Matthias T.

AU - Imasato, Kazuki

AU - Anand, Shashwat

AU - Lee, Kathleen

AU - Bux, Sabah K.

AU - Zevalkink, Alex

AU - Rettie, Alexander J.E.

AU - Chung, Duck Young

AU - Kanatzidis, Mercouri G

AU - Snyder, G. Jeffrey

PY - 2018/8/1

Y1 - 2018/8/1

N2 - The thermoelectric figure of merit reported for n-type Mg 3 (Sb,Bi) 2 compounds has made these materials of great engineering significance, increasing the need for accurate evaluations of their thermal conductivity. Thermal conductivity is typically derived from measurements of thermal diffusivity and determination of the specific heat capacity. The uncertainty in this method (often 10% or more) is frequently attributed to measurement of heat capacity such that estimated values are often more accurate. Inconsistencies between reported thermal conductivity of Mg 3 (Sb,Bi) 2 compounds may be attributed to the different values of heat capacity measured or used to calculate thermal conductivity. The high anharmonicity of these materials can lead to significant deviations at high temperatures from the Dulong-Petit heat capacity, which is often a reasonable substitute for measurements at high temperatures. Herein, a physics-based model is used to assess the magnitude of the heat capacity over the entire temperature range up to 800 K. The model agrees in magnitude with experimental low-temperature values and reproduces the linear slope observed in high-temperature data. Owing to the large scatter in experimental values of high-temperature heat capacity, the model is likely more accurate (within ±3%) than a measurement of a new sample even for doped or alloyed materials. It is found that heat capacity for the solid solution series can be simply described (for temperatures: 200K≤T≤800K) by the polynomial equation: c p [Jg −1 K −1 ]=[Formula presented](1+1.3×10 −4 T−4×10 3 T −2 ),where 3NR=124.71Jmol −1 K −1 , M W is the molecular weight [gmol −1 ] of the formula unit being considered, and T is temperature in K. This heat capacity is recommended to be a standard value for reporting and comparing the thermal conductivity of Mg 3 (Sb,Bi) 2 including doped or alloyed derivatives. A general form of the equation is given which can be used for other material systems.

AB - The thermoelectric figure of merit reported for n-type Mg 3 (Sb,Bi) 2 compounds has made these materials of great engineering significance, increasing the need for accurate evaluations of their thermal conductivity. Thermal conductivity is typically derived from measurements of thermal diffusivity and determination of the specific heat capacity. The uncertainty in this method (often 10% or more) is frequently attributed to measurement of heat capacity such that estimated values are often more accurate. Inconsistencies between reported thermal conductivity of Mg 3 (Sb,Bi) 2 compounds may be attributed to the different values of heat capacity measured or used to calculate thermal conductivity. The high anharmonicity of these materials can lead to significant deviations at high temperatures from the Dulong-Petit heat capacity, which is often a reasonable substitute for measurements at high temperatures. Herein, a physics-based model is used to assess the magnitude of the heat capacity over the entire temperature range up to 800 K. The model agrees in magnitude with experimental low-temperature values and reproduces the linear slope observed in high-temperature data. Owing to the large scatter in experimental values of high-temperature heat capacity, the model is likely more accurate (within ±3%) than a measurement of a new sample even for doped or alloyed materials. It is found that heat capacity for the solid solution series can be simply described (for temperatures: 200K≤T≤800K) by the polynomial equation: c p [Jg −1 K −1 ]=[Formula presented](1+1.3×10 −4 T−4×10 3 T −2 ),where 3NR=124.71Jmol −1 K −1 , M W is the molecular weight [gmol −1 ] of the formula unit being considered, and T is temperature in K. This heat capacity is recommended to be a standard value for reporting and comparing the thermal conductivity of Mg 3 (Sb,Bi) 2 including doped or alloyed derivatives. A general form of the equation is given which can be used for other material systems.

KW - Heat capacity

KW - Mg Bi

KW - Mg Sb

KW - Thermal conductivity

KW - Thermoelectric

UR - http://www.scopus.com/inward/record.url?scp=85055578832&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85055578832&partnerID=8YFLogxK

U2 - 10.1016/j.mtphys.2018.10.001

DO - 10.1016/j.mtphys.2018.10.001

M3 - Article

VL - 6

SP - 83

EP - 88

JO - Materials Today Physics

JF - Materials Today Physics

SN - 2542-5293

ER -