Determination of thermal diffusivity of low-diffusivity materials using the mirage method with multiparameter fitting

Abstract

Articles you may be interested inLow temperature thermal diffusivity measurements of transparent solids and gases by the mirage technique AIP Conf. Low temperature thermal diffusivity measurements of gases by the mirage technique Rev. Sci. Instrum. 70, 98 (1999); 10.1063/1.1149548Low thermal diffusivity measurements of thin films using mirage technique A method to determine anisotropic thermal diffusivities parallel to the surface of a solid sample is presented. The measurement method is based on the mirage effect and the data are analyzed using multiparameter least-squares regression fitting. The specimens studied were of medium and low diffusivity: rare earths, ceramics, and polymers. Before this study, the low-diffusivity limit for the applicability of the mirage method was about 0.02 cm2/s, and therefore this technique has not been suitable for polymeric materials. In this work the limit has been reduced to 5 X 10V4 cm2/s by improving the measurement apparatus and the data analysis method. The thermal diffusivities obtained agree with the values obtained using the flash method within f 20%. The agreement with published values is good, taking into account that for ceramics and polymers the literature gives only the correct order of magnitude due to the differences in the manufacturing process. Even though the sensitivity of the measurement decreases with the decreasing diffusivity, the thermal diffusivity of bulk polymers can still be determined within an accuracy of 10%. For polymer foils the method has been found to be reliable when the foil thickness exceeds 100 pm.

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

“…In this work, a multiparameter fitting scheme has been employed to determine the thermal diffusivity by the mirage technique [9]. Details of the principles of the mirage measurement can be found elsewhere [9][10][11]. Figure 2 shows the experimental setup for the ac calorimetric method.…”

“…An analytical solution to the three-dimensional heat conduction problem considering the heat conduction in air as well as in the sample [10] has thus been employed to determine the thermal diffusivity. In this work, a multiparameter fitting scheme has been employed to determine the thermal diffusivity by the mirage technique [9]. Details of the principles of the mirage measurement can be found elsewhere [9][10][11].…”

Coating thermal diffusivity and effusivity measurement optimization using regression-based sensitivity

“…Material properties are often determined through regression analysis. [1][2][3][4][5][6][7][8][9] The sensitivity of a measurement to the properties of interest can be established with the following definition offer by Beck: 9 Suppose that a temperature measurement T i is taken at a specific time and location in the material, the sensitivity of a material property x j to this measurement is defined by the slope ∂T i /∂ x j . Ideally the magnitude of this slope is large, corresponding to a high sensitivity that minimizes the uncertainty in measurement results.…”

Vector model analysis in nondestructive imaging by using the photothermal deflection methods

“…The thermal parameters can be obtained in the photoacoustic techniques [9]. Thermal diffusivity is obtained from the modulation frequency dependence of photoacoustic signals [10,11]. The thermal properties are analyzed at the plasma-sprayed zirconia coating [12].…”

“…Furthermore, one can get the depth profile of signals by changing the modulation frequency. Although the thermal properties were obtained from the modulation frequency dependence of the PTD signals in the scanned images until now [10,11], we apply the vector model [15] to the scanning imaging methods and calculate the thermal diffusivity. In this paper, we report on the imaging of the buried structure by the PTD method and calculate the thermal properties of the sample using both the PTD amplitude signals and the phase signals.…”