History.1 – Transient Plane Source Method- Part 1

Jun 15, 2015 | Blog, History |

With the ever-increasing number of materials being used in wide temperature range applications, the need for rapid development and knowledge to improve the thermophysical properties of these materials is of most importance for researchers.

Following the work of Dr. Silas E. Gustafsson and his group1-9 at the Department of Physics of the Chalmers University of Technology in Gothenburg, Sweden back in 1995, the transient plane source method was first introduced and ISO-certified in 2008.

This new method offered scientists the ability to directly measure thermal properties such thermal conductivity, thermal diffusivity, and specific heat capacity with more ease and precision. The new instrumentation allows for both in laboratory and in-situ measurements of solids, liquids, powders, and paste from cryogenic to extremely high temperature (1000K) with resulting thermal conductivities of 0.01 to 500 W/m·K. This method also has the ability to test both isotropic and anisotropic materials.

Thermal Conductivity Blog TPS 3500 4

Figure 1. TPS 3500, the latest addition to the Hot Disk® instrumentation family.

Alongside this new methodology, the TPS involves the use of a very thin nickel double spiral that is placed between two layers of Kapton, about 25 µm in thickness. The sensor is then either sandwiched between the investigated materials or measured single-sided to the material. The double metal spiral serves both as the heat source and as a resistance thermometer. Scientists should be aware that the samples are normally homogeneous, but extended use of the TPS testing method for heterogeneous materials is possible with proper selection of sensor size to maximize the sample penetration. 

Thermal Conductivity Blog Transient Method Comparison 1

Figure 2. Comparison of a two-sided Kapton sensor embedded into sample material and one-sided testing sensor.




Image Reference