Hello everyone! In this video, I'm going to show you How I made liquid metal for computer Central Processing Units And how I tested it's thermal conductivity In case you didn't know Modern computers transfer heat from CPU to radiator through a layer of thermal interface material Most frequently thermal grease is used as such a material And obvious disadvantage of thermal grease is that it has very low thermal conductivity which at least 5 times slower than that of tin solder It is so due to the powder components it contains It is especially useful in our days because INTEL CPU are not soldered to heat transferring caps Otherwise, they are glued to it, with silicon And heat is transfer through thermal grease because of that, heat is transfer not very efficiently to the cap Besides thermal grease, there also exist liquid metal, which transfer heat much better than the thermal grease However, it is 10 times more expensive, that is why I decided to make my own liquid metal and *upload?* it, to share with you, my viewers, all the secrets of it's production Nowadays, liquid metal sold in computer shops for *???* users, it is gallium based Gallium is a metal, which has a very low melting point of just 30℃ However, when held in hands, your gallium does not melt as quickly as one will do expect I think you have seen lots of experiments with this element If gallium is *wrap?* against another metal such as indium from the group 13 in the periodic table They will form an alloy, which is liquid at the room temperature, In the place of our both metal contact It can also be called an eutectic solution It is 24.5% indium, and 75.5% gallium It's melting point is 16℃ It's interesting that the piece of gallium goes down significantly The habit due to the distraction of it's crystalline grade At the room temperature, this alloy remains liquid But, only at 16℃, which is not that low, for instance, when the centralized heating system is shutdown, this alloy will solidify, on a chilly summer day That is why in order to further reduce melting point of the alloy, engineers have come up with an idea to add tin to the alloy of indium and gallium The alloy is 68% gallium, 22% indium and 10% tin It even has its own name, galinstan. This very alloy is used as thermal interface material, and is called liquid metal It is quite easy to make, you just need to mix all the components and heat it up First, I heated up the alloy in a heated bath, however beads of tin didn't dissolve But, when I used a burner, the alloy mixed together well and became smooth Melting point of such an alloy is much lower than that of the previous alloy, and it's about -19℃ However this fact is open to debate because *???* of the melting point might also be interrupt to bismuth and antimony impurities that the metals may contain That is why there may be some flotations However, *that obtained?* galinstan wets difference surfaces very well That is why it is easy to distinguish it from mercury Besides, in contrast to mercury, galinstan is absolutely safe and non-toxic This alloy can be used for draw conductive tracks on paper, their electrical resistance will be much lower than that of graphite tracks Besides, this alloy isn't very viscous, that is why it can be easily sucked in with an insulin needle Now, let us test heat conductivity properties of such a DIY alloy I have prepared such a experimental setup, I'm using my old core i3-540 CPU manufactured in 2011 I'm using no ordinary radiator otherwise such a nickle plated one which will contact with the CPU An aluminum radiator is not to be used with liquid metal Because gallium which it contains destroys aluminum's crystalline grades, making aluminum fragile To demonstrate how this happens, I took one aluminum radiator, and put a drop of galinstan on it After that, I left it like this one for a week One week later, you can see that the galinstan drop has slightly oxidized, and the radiator itself has become very fragile It is very easily breaks in hands, imagine what it will be like if your computer's cooler and radiator suddenly fell off A nickle plated radiator can easily prevent such a problem After preparing the setup, first, I applying a regular thermal grease to the CPU which comes along with it as a thermal interface material
