Cold Welding Metals In a Vacuum

hey everyone today i'm going to be attempting cold welding let's turn off the vacuum and see if they lock together so normally metals like this aluminum here are held together because there's a crystalline structure of positive metallic ions and then there's a sea of negative electrons throughout it and this creates a very strong bond that holds everything together now technically if you were just to take some metallic ions and bring some other of the same metal close together they would just get so close and then the electrostatic attraction would pull them together just as if it were part of the same metallic structure altogether so when i push these two pieces of aluminum together they should stick together but they don't now the reason they don't stick together is because i'm not actually pushing the aluminum together i'm actually pushing two pieces of aluminum oxide together so on the surface of this aluminum is a very thin layer of aluminum oxide that has reacted with the oxygen in the air and so i can't actually get these metallic ions close enough together to actually form that electrostatic attraction to be pulled together into the same group but if you're able to remove the air from between these so that there's no aluminum oxide then if you just push them together they should just weld together as if they were the same metal and this is called cold welding and it actually turned out to be a problem for a lot of early satellites that they built in space where there's a vacuum in 1991 the galileo spacecraft which was sent to jupiter to monitor jupiter and then was going to be sent into its atmosphere it deployed its high gain antenna what was supposed to happen on this galileo antenna is that when they released the holding mechanism for the antenna it was supposed to pop out similar to an umbrella but what happened is that it didn't pop out it got stuck like this and it never really opened even though they had tested it a lot before obviously before it was launched they found that it never opened in space after two years of researching this problem on earth and trying to figure out what happened they finally found out it was a series of unfortunate events but one of the main causes was that they used titanium and titanium reacts very quickly with air and forms titanium oxide and it doesn't have the same coefficient of friction as pure titanium that doesn't have titanium oxide in it so they didn't do enough tests in a vacuum when they were testing the release mechanism to know it would slide well but when they did it in a vacuum it didn't slide as well so today i'm going to be trying to make cold welding happen in a vacuum and then i'll be trying to actually make it happen in air with a specific type of metal called indium okay so in order to do this i have two pieces of gallium metal here and gallium already doesn't form a lot of oxide on the surface and so that won't be there but there's still air in between these two metal crystals here and so when i touch them together they don't stick but let's see what happens when i put them together in the vacuum chamber now i'll probably still need a little force on them so i'm going to be using my large neodymium magnet here and then my even larger neon give me a magnet from below look how far away it affects it that's so crazy so i don't want to let these two touch each other without this layer of acrylic between them i'll never get them apart so i'm going to be sticking this under it and i'll put my magnet on top and then i'm gonna lift this up close to it oh my goodness okay but i don't want that to happen i want the magnet to stay on top of it so it should happen a little bit more stable like that and it should press them together in the vacuum chamber notice how they're not stuck to each other in the air after that but now let's do it under vacuum okay turn on the vacuum three two one okay we've got a really good vacuum in there now okay put some pressure on it for a bit leave it under the vacuum and see if we can get them to cold well together okay let's carefully take the magnet off easy it didn't stick okay so that didn't work but i think it's because i need to put a little bit more mechanical pressure on it and even turn them a little bit bit to wiggle them together and get the grooves to go into each other a little more and so i'm going to actually vacuum bag them instead of using my vacuum chamber so it'll put pressure on it from the atmosphere and then i'll also be able to press them together as well so let's see if we can actually cold weld them together by vacuum backing them okay they're vacuumed on top of each other okay let's turn off the vacuum and see if they lock together uh they look kind of stuck together they're not slipping off open our bag here oh look at that they're stuck together we did it cold welding cold welding in a vacuum look at that two pieces of gallium stuck together without any application of heat here we were able to cold weld these okay let's see how hard they are to actually pull apart oh they just came right apart so they weren't actually bonded together very well but on the surface there they were bonded so i can kind of fill them stick together in the air but they were very easily able to come together and form a cold weld under the vacuum there now remember gallium melts at 85 degrees celsius but i'm doing this experiment well below 85 degrees celsius it's around 60 degrees in here so it won't make the gallium melt at all so the ability for this to melt has nothing to do with the cold welding here it's actually more to do with the ability to not form a gallium oxide on the surface now the cool thing about cold welding is you don't actually need a vacuum chamber to do it there are some metals in which you can cause to cold weld together even in air now they have to be softer metals and they can't form a lot of oxides on the surface now one of these metals is called indium indium is an extremely soft metal i have here two one ounce ingots of indium these two pieces of indium ingots don't stick together at all but if you actually put them together and give them a little twist then they stick on the very flat surface of it if i just touch them together and set them on top of each other they stick together so weird so they're not attracted to each other in any way it's not like these are magnets or anything but if you just bring those flat surfaces together they stick and if you give them a little twist you can get them to cold well together or gall together really strong actually so i almost can't get these apart they're stuck but if you do it to a dissimilar metal because the crystal structures are different it won't gall together or cold weld together now this is actually a form of cold welding it's more related to something called galling galling is when you have enough frictional force between two metals that they can actually bond together now galling and cold welding are actually not separate phenomena but they're actually kind of the same thing galling just takes place when you have a lot of friction in between the two metals and it can even happen with regular metals like steel or aluminum you can get it to happen pretty easily with indium because it's a lot softer metal in fact i have a previous video where i actually chewed indium like a stick of gum that's pretty cool hey everyone thanks for watching another episode of the action lab i hope you enjoyed it if you did don't forget to hit the subscribe button if you haven't subscribed to my channel and also if you haven't yet hit the bell so you can be notified when my latest video comes out and turn on your youtube notifications or the bell doesn't help and also check out the actionlab.com to see my new action lab experiment boxes where you can do experiments similar to the ones that you see me do in my channel here and thanks for watching and i'll see you next time

Channel: The Action Lab

Views: 655,076

Keywords: cold welding, vacuum chamber, cold welding definition, gauge blocks, cold welding explanation, international space station, galling, the action lab, gallium, indium, cold welding in space

Id: pavp6dps6q0

Length: 9min 59sec (599 seconds)

Published: Wed Nov 25 2020