Test results and strange anomalies
I have packed the material sample into the TIMA5 and am now waiting for the things that are about to come. Based on all the reviews of this card (we also know what the Gallardo delivered after my re-paste), it can be assumed that the original paste used must have a very high thermal conductivity, i.e. a very low thermal resistance. The test must now show how good this is. The picture below shows the paste, which starts to run and drip after a short time and without any external influence. I have never really experienced anything like this before.
Let’s look at the initial analysis of my measurements at 60 °C paste temperature as a TIMA summary. As always, I always test different layer thicknesses of the paste, starting at 400 µm and then in 25 µm steps down to 25 µm. This is also the case here. The green dots for the thermal resistance show a very linear curve, which is ideal in this form. I then test in a run at 60 PSI (41 N) how far the paste can still be compressed in order to be able to draw conclusions about the approximate particle size of the fillers at this point, because at this pressure the matrix can already be more or less excluded. However, this was the end at around 16 to 20 µm. Ordinary pastes, however, are around 10 or significantly less µm. This can also be seen in the anomaly of the thermal resistance, which is no longer on the line.
This already made me suspicious, because this is not really normal in this form. But I can turn the TIMA5 into a pressing plant, so to speak, and increase the pressure significantly. However, I shouldn’t do this too often so as not to ruin the surface of the test specimens. At around 300 N on the one cm², it went a little further to end at around 5 µm. I raised the body once more to around 100 µm and then lowered it again without encountering the barrier I had already overcome once before. A second attempt with paste pressed out of the side stopped again at the already known 16 to 20 µm. However, I aborted this in order to protect the technology (surfaces). After all, the TIMA5 is not a coffee grinder and certainly not a mortar.
The bulk thermal conductivity of approx. 4.6 W/(m-K) is outstanding, and the interface resistance of around 5 mm²K/W is also pleasing, but unfortunately much too low to be normal. From 7 mm²K/W would be normal, but this is also very suspicious because it is still below the PCM.
Now I have the individual ratings as graphics for you, which attest to very good to above-average values for this paste in the initial stage of use. However, the thermal resistance up to around 135 µm is still below that of the excellent but already very viscous Thermalright TF8, but then increases significantly as the layer thickness increases, which is also very suspicious:
The resulting effective thermal conductivity exhibits the same anomaly, where this value suddenly increases significantly less as the layer thickness increases. This in turn is not normal in this form and requires further investigation.
That’s exactly what I’ll do now and show you the result after turning the page…
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