Phil Zarrow: This video is for researchers and engineers interested in indium metal. It will cover the applications and future uses.
Ron, can you tell us a little bit about the history of indium metal? How was it discovered?
Dr. Ronald C. Lasky: In 1863, Reich and Richter were looking at some metal alloys with a spectrometer, and they found a blue, actually indigo color line, that shouldn't have been there. They rightly assumed that they had discovered a new metal, and they named it indium because the line was indigo.
Phil Zarrow: What are some of the uses of indium?
Dr. Ronald C. Lasky: The Indium Corporation was the first company to find a practical use for indium in the 1930s, and that was for bearing lubricants in aircraft, and also it was used in solders and fusible alloys. The combination of indium, tin, and a few other elements like bismuth, you can essentially get a solder that will meld at just about any temperature.
Phil Zarrow: I understand it's a very soft alloy.
Dr. Ronald C. Lasky: Yeah. If you look at it. This is indium itself. Phil, take your fingernail yourself and you can scratch it real easy with your fingernail. There's also something called indium cry. When you bend this bar, you can hear that the indium speaking out to us with its indium cry.
Phil Zarrow: You mentioned indium tin oxide, in one of our earlier discussions, as a modern application of indium. What are some of the other modern applications?
Dr. Ronald C. Lasky: One of the things I'm sure you're aware of, Phil, in all of our works and electronic assembly, is one of the issues with electronics is often getting the heat out. This is an old circuit board that has a microprocessor in. The microprocessor here generates a lot of heat, and it needs to conduct this heat out through heat fins. To make a thermal path from the microprocessor to the heat fins, something called thermal grease is used – or, was used.
Phil Zarrow: Was used.
Dr. Ronald C. Lasky: It's really a poor conductor. It has poor mechanical properties, it can ooze out, and so one of the more modern developments has been using what is called thermal interface material, where you take some indium, indium alloy, and you put it between the semiconductor and the heat fins. You just put mechanical pressure on it, and the indium alloy being a very soft material, will flow into all the little cracks and crevices and make a very effective thermal path for getting the heat out of the semiconductor.
Also, another aspect of indium is it's one of the few metals that will bond mechanically to glass and seal the glass. In some electrical applications that we talked about – flat panel displays – there are cases where they need a metal that will bond to glass and it will do that. Also, indium is used in semiconductors also.
Phil Zarrow: How about some of the more unusual applications? What comes to mind?
Dr. Ronald C. Lasky: It actually can be used as a superconductor, and it has a high nuclear cross-section for neutrons, and so it's often used in nuclear control rods.
Phil Zarrow: Wow. For a material that's not exactly a household word, indium is probably one of the most important metals in the modern world.
Dr. Ronald C. Lasky: Yeah, absolutely true. And, for those that that are interested in finding more information about indium, they can find it at www.indium.com.
Phil Zarrow: Good place to go. Fascinating as usual, Ron. Thank you.
Dr. Ronald C. Lasky: Thank you.