I Need help to explain the peak of thermal conductivity

1. May 6, 2018

sunmaggot

Progress
This is the experimental data of thermal conductivity of stainless steel 304L at low temperature. The data is calculated with the Fourier's law of thermal conduction. I checked many times in the excel file and I confirmed that there is no mistake in the calculation. The parameters are also correct. What I see in here is that the sample used has much higher thermal conductivity than it should be. I compared with different reference and they all show that at 300K, the K should not exceed 16. So I concluded that this sample has below standard impurities level.

Problem
However, there is a strange peak at around 190K. That data is not one data. I did around 9 data at that point and it shows that the K is really higher than the nearby data point. Then I need to explain this peak. I tried to relate this with the thermal conductivity of the chemical composition. However, the position of the peak is at 190K. The change in thermal conductivity for different material should not be vigorous at this temperature. How can I possibly explain such phenomenon?

2. May 9, 2018

Staff: Mentor

I'm sorry you're not getting answers. I don't know of any such peaks.

3. May 9, 2018

dRic2

I don't understand why you are so sure it is not a problem of the algorithm you used to integrate numerically the diff. equation. I'm not an expert, but 190K is a very low temperature... I don't see how any properties (thermal conductivity, heat capacity, viscousness...) should behave like that. I would try to change the algorithm.

If it is real though, there must be a very cool explanation!! Hope you'll come up with something!

4. May 11, 2018

Tom.G

Is 190K near a phase change temperature of any gasses in the experimental environment?