My dad is an expert in pottery, so he knows _a lot_ of chemistry but it is fairly specialized.
So I find a cool article that says that a substance (that *I* never heard about before) is used in computers due to it's high heat resistance, and he is like "what, but it is not heat resistant at all! It melts under 1000 celsius!" and I have to remind him that computers should never ever get anywhere close to 1000 celsius.
@eldaking Now I'm curious what the material is, as someone who works with electronics and is currently focused on thermal issues!
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@Felthry I don't remember the details, and I am summarizing a bunch of different things..
Recently I was showing him thermal paste and he was just underwhelmed by every substance used (most of which I didn't know). Some of the oxides they use for thermal conduction are thermal insulators for him.
And I think I have mentioned the "high" melting point of copper, maybe even aluminum, a few times and he disagrees vehemently every time.
@Felthry Maybe it was the silicone in the thermal paste that couldn't stand to 1000 celsius? Or maybe the silver that some of them add.
@eldaking Silicone can handle pretty high temperatures, but I'm pretty sure a thousand degrees is too much even for it.
I'm a little surprised about that last bit though! Most of the thermal ceramics used are either aluminum nitride or beryllium oxide (sometimes also aluminum oxide because it's cheaper and nontoxic but it's nowhere near as good), which are the top two thermal conductivities known in ceramic materials
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@eldaking ah sorry i got a little bit infodumpy there
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@Felthry Yeah, it's mostly there to fill air gaps, it has to spread well and be less bad than air. I explained it to him and he got it - but I guess he was expecting this fancy substance to have something more esoteric.
It might have been aluminum oxide, which as corundum is used as a refractory? I remember he talked about it because it came up again the other day when he was showing me the ways in which people fire ceramics in microwave ovens.
@eldaking Aluminum oxide is a comparatively poor thermal conductor, but it's much cheaper than the nitride, and doesn't have the (*extreme*) toxicity of beryllium oxide, so it's somewhat popular for making things like ceramic heatsinks out of. I'd still rather use an AlN one when possible, though!
It's really a shame diamond is so expensive. It's got the highest thermal conductivity of any substance known, afawk, and solid diamond heatsinks would solve so many problems.
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@Felthry Yeah, I was googling around a bit and I think I might have misremembered he saying it was a refractory as it being an insulator. Aluminum oxide I'm vaguely familiar with, but not "corundum" in particular which is particularly useful for some kilns... and I guess he wouldn't think of it for heatsinks. Or maybe I am misremembering more details, I was quite out of my depth.
@eldaking corundum is just another name for aluminum oxide, which is also called sapphire (or ruby, if it has specific impurities in it)
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@eldaking still, thermal paste is mostly used to get a good interface and nothing more, and that's for good reason--you really can't beat aluminum, copper, or dymalloy when it comes to thermal conductivity, so you try to get the heat into a heatsink made of one of those with as little stuff in the way as possible
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