We Now Have The First-Ever Permanently Magnetic Liquid MICHELLE STARR 19 JUL 2019 Science Alert https://www.sciencealert.com/scient...il&utm_term=0_fe5632fb09-1ba1f49197-365873681 What has the magnetic properties of a solid magnet, but the mechanical properties of a liquid? If you answered 'nothing,' you're wrong - because engineers have just created just such a substance, by using a modified 3D printer.
That looks really clever, but not really the "First Ever" application of this concept, Magneto-rheological fluid. GM first applied this technology in 20031 to Corvette suspension damping, and has been using ever since on higher-end vehicles for on-the-fly control of shock absorber damping rates. Originally developed by Delphi, the MagneRide2 products are now produced by a Chinese firm called BWI, or Beijing West Industries. Anyway, thanks for posting, this is another example of how one newer technology (3D Printing) has been useful for seeding creativity in ways never expected by its originators. Cheers, David / N2PQW Links: 1: https://www.motortrend.com/news/for...e-history-of-gm-magnetic-ride-control-318181/ https://www.nydailynews.com/autos/street-smarts/what-is-magnetic-ride-control-article-1.4042612 2: http://www.magneride.com/
I saw a magnetic liquid at the fishing counter of Kittery Trading Post earlier this year. It is used as a seal and lube for some pretty nice fishing reels.
Hmm. Not sure how "new" this is. Maybe I'm missing something. I've been polishing glass with Magneto-rheological liquids for 10 years now.The rotary actuator feedthrough seals (Ferrofluidic Feedthrough) on our vacuum chambers have been in use for at least 25 years. Doesn't any ferrous material held in suspension have the potential to retain magnetism? Perhaps the original poster could enlighten me. -Jack, ars: WA2RZG Idex Health and Science, Optics Rochester NY
The new part is that the particles can retain their magnetism when the external H field is removed. In other words they have significant remanance, and therefore have some properties similar to familiar permanent magnets. The usual ferrofluid such as used in a seal has particles too small (sub-domain size) to have significant remanance.
Interesting article. I can remember reading about the use in the Corvette suspension years ago but had let that slip from memory till I saw your post.
Ferrofluid has been used in the magnetic gap of certain high-end loudspeakers and compression drivers for over 25 years. It serves two purposes. It helps cool the voice coil, and it raises efficiency because the voice coil is actually immersed in the magnet. Here's a link to the manufacturer: https://www.ferrotec.com/company/about/history/
