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Thermal Conductivity during Phase Transitions
Author(s) -
Chen Hongyi,
Yue Zhongmou,
Ren Dudi,
Zeng Huarong,
Wei Tianran,
Zhao Kunpeng,
Yang Ronggui,
Qiu Pengfei,
Chen Lidong,
Shi Xun
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201806518
Subject(s) - thermal diffusivity , thermal conductivity , materials science , phase transition , thermodynamics , thermal conduction , phase (matter) , thermal , thermal resistance , thermal transmittance , thermal effusivity , condensed matter physics , thermal contact conductance , composite material , chemistry , physics , organic chemistry
Thermal conductivity is a very basic property that determines how fast a material conducts heat, which plays an important and sometimes a dominant role in many fields. However, because materials with phase transitions have been widely used recently, understanding and measuring temperature‐dependent thermal conductivity during phase transitions are important and sometimes even questionable. Here, the thermal transport equation is corrected by including heat absorption due to phase transitions to reveal how a phase transition affects the measured thermal conductivity. In addition to the enhanced heat capacity that is well known, it is found that thermal diffusivity can be abnormally lowered from the true value, which is also dependent on the speed of phase transitions. The extraction of the true thermal conductivity requires removing the contributions from both altered heat capacity and thermal diffusivity during phase transitions, which is well demonstrated in four selected kinds of phase transition materials (Cu 2 Se, Cu 2 S, Ag 2 S, and Ag 2 Se) in experiment. This study also explains the lowered abnormal thermal diffusivity during phase transitions in other materials and thus provides a novel strategy to engineer thermal conductivity for various applications.