Ingenious Method for Eliminating Effects of Heat Loss in Measurements of Thermal Diffusivity by ac Calorimetric Method

Gu, Yi; Tang, Xiaowei; Hatta, Yuan Xu

doi:10.1143/jjap.32.l1365

Cited by 29 publications

(12 citation statements)

References 6 publications

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“…(10) and (11), respectively. 22) In the case of spot heating, let us consider the experimental requirements for obtaining the true k in a similar way. The apparent decay constant, k a,app , derived from eq.…”

Section: Analysis Of Theoretical Resultsmentioning

confidence: 99%

Measurement of Thermal Diffusivity in a Sample with a Certain Thickness by an AC-Calorimetric Distance-Variation Method: IV. Requirements for Measuring by Spot Heating

Takahashi¹,

Hamada

Hatta

2004

Jpn. J. Appl. Phys.

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An ac-calorimetric distance-variation method has a variety of applications in thermal diffusivity measurement of a plate like material. In this method, there are some ac heating configurations. For a periodic band heating and a periodic line heating, we have proposed the requirements for the precise measurement in our previous papers. In this paper, we analyze temperature wave propagation in a plate like sample for a periodic spot heating under the condition in which heat loss between a sample and a heat sink takes place. In such a case, the requirements for measuring thermal diffusivity by spot heating within an accuracy of AE1% are proposed. For the precise measurement, we analyze the requirements in detail for the cases using only the phase of the periodic temperature and both the phase and the amplitude, because these two methods have individual merits.

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Section: Analysis Of Theoretical Resultsmentioning

confidence: 99%

Measurement of Thermal Diffusivity in a Sample with a Certain Thickness by an AC-Calorimetric Distance-Variation Method: IV. Requirements for Measuring by Spot Heating

Takahashi¹,

Hamada

Hatta

2004

Jpn. J. Appl. Phys.

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“…In the distance-variation method, it has been proposed that we can obtain straightforwardly the true k from the correction of the heat loss by taking the geometrical average of the decay constant k a and phase shift k p as 25) k…”

Section: Ac Calorimetric Distance-variation Methodsmentioning

confidence: 99%

Characterization of Heat Conduction in a Polymer Film

Takahashi

Itô

Morikawa

et al. 2004

Jpn. J. Appl. Phys.

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In-and cross-plane thermal diffusivities of a plate like material in the directions parallel to the plane surface and perpendicular to the plane surface can be obtained using an ac-calorimetric distance-variation method and a temperature wave analysis method, respectively. In this study, we carried out the thermal diffusivity measurements of commercially available polyimide films in both direction as a function of thickness. As expected, the in-plane thermal diffusivity is larger than the cross-plane thermal diffusivity. The in-plane thermal diffusivity is larger in an advanced polyimide film with a high tensile strength threshold and a low elongation percentage than in a standard polyimide film with a low tensile strength threshold and a high elongation percentage. The cross-plane thermal diffusivities are almost the same between an advanced polyimide film and a standard polyimide film. Therefore, cross-plane thermal diffusivity is not markedly influenced by the detailed features of a polyimide film. Furthermore, in-plane thermal diffusivity decreases slightly but clearly as the film becomes thicker, but crossplane thermal diffusivity remains almost constant against the film thickness. The measurement of thermal diffusivity is a useful method of characterizing heat conduction in a polymer film.

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“…Gu et al [7] showed that the thermal diffusivity of the sample in this situation is given by the geometric mean of the two apparent thermal diffusivities, one obtained from the amplitude decay and the other from the phase shift, i.e.,…”

Section: Thermal Diffusivity Measurementmentioning

confidence: 99%

Thermal Diffusivity of Metallic Thin Films: Au, Sn, Mo, and Al/Ti Alloy

2006

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The thermal diffusivity of Au, Sn, Mo, and Al 0.97 Ti 0.03 alloy thin films, which are commonly used in microelectromechanical (MEMs) system applications, is measured by two independent methods -the ac calorimetric and photothermal mirage methods. Both methods yield similar results of the thin-film thermal conductivity, but the uncertainty of the mirage technique is found to be relatively large because of the large temperature increase during the measurement. The measured thermal diffusivities of the thin films are generally lower than those of the same bulk material. Especially, the Al 0.97 Ti 0.03 thin film shows a pronounced thermal conductivity drop compared with bulk Al, which is believed to be mainly due to impurity scattering. Comparison of the thermal conductivity with the electrical conductivity measured by the standard four-probe technique indicates that the relation of thermal and electrical conductivities follows the Wiedemann-Franz law for the case of Au and Sn thin films. However, the Lorentz number is significantly larger than the theoretical prediction for the case of Al 0.97 Ti 0.03 and Mo thin films.

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Ingenious Method for Eliminating Effects of Heat Loss in Measurements of Thermal Diffusivity by ac Calorimetric Method

Cited by 29 publications

References 6 publications

Measurement of Thermal Diffusivity in a Sample with a Certain Thickness by an AC-Calorimetric Distance-Variation Method: IV. Requirements for Measuring by Spot Heating

Measurement of Thermal Diffusivity in a Sample with a Certain Thickness by an AC-Calorimetric Distance-Variation Method: IV. Requirements for Measuring by Spot Heating

Characterization of Heat Conduction in a Polymer Film

Thermal Diffusivity of Metallic Thin Films: Au, Sn, Mo, and Al/Ti Alloy

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