Local measurement of thermal conductivity and diffusivity

Area of Science:

• Materials Science
• Thermal Physics
• Nuclear Engineering

Background:

• Accurate thermal property measurement is vital for developing advanced nuclear fuels.
• Existing methods may lack precision or require extensive sample preparation.

Purpose of the Study:

• To demonstrate a novel technique for simultaneous measurement of local thermal diffusivity and conductivity in ceramic materials.
• To validate the technique's applicability to materials relevant to accident-tolerant nuclear fuels.

Main Methods:

• Utilized amplitude modulated continuous wave laser excitation to measure the temperature field spatial profile.
• Applied a thin gold film for enhanced optical absorption and to introduce a boundary condition for thermal conductivity.
• Compared measured phase profiles to a continuum model, incorporating Kapitza resistance for improved accuracy.

Main Results:

• Successfully measured thermal diffusivity and conductivity on various ceramic samples.
• Achieved close agreement with literature values by including Kapitza resistance as a fitting parameter.
• Demonstrated that the technique does not require prior knowledge of optical spot size, enhancing reliability.

Conclusions:

• The developed laser-based method provides a reliable and reproducible means for simultaneous thermal property determination.
• This technique is suitable for characterizing materials used in advanced accident-tolerant nuclear fuels.
• The method's independence from optical spot size knowledge simplifies measurements and improves accuracy.