Talk:Ferrofluid

message: This page is need of some heavy editing since it contains a lot of errors. I was about to start, when I realized it was more work than I asked for. The structure of the article is quite bad and there is a lot of duplicate sentences and plain fact errors. Also most of the chemistry in the article is way off. Hematite is an antiferromagnetic phase and can not be used to form ferrofluids. The physics and chemistry of ferrofluids and magnetorheological fluids are a firmly established research fields and ferrofluids deserves a decent wikipedia entry. I will try to do what I can to tidy up/edit this page in the coming weeks and add some of the great references in on the topic astrolux (talk) 19:40, 5 July 2010 (UTC)
thread_title: Major revisions needed

message: I watched the 4th season's 15th episode "DOA for a Day".  in the episode, ferrofluid is identified because it is "sensitive to sound".  While I strongly beleive this is inaccurate, can anyone specifically discount this.   —Preceding unsigned comment added by 65.101.183.104 (talk) 01:39, 20 October 2008 (UTC)
replies: text: They are used in loudspeakers to sink heat between the voice coil and the magnet assembly, and to damp the movement of the cone. They reside in what would normally be the air gap around the voice coil, held in place by the speaker's magnet. Using electromagnets and sensors, the fluid's viscosity can be controlled dynamically. This allows hundreds of watts of mechanical power to be controlled with a few watts of electrical power, which is much more efficient than other methods of vibration control, such as piezoelectric crystals.
to my understanding, ferrofluid does not change viscosity under different magnetic fields, and is not used in that way to damp speakers.  i think MR fluid is used to damp car shocks in that way, but it's not the same kind of damping. - Omegatron 02:49, Jul 8, 2004 (UTC)
Actually a ferrofluids viscosity does change under the influence of a magnetic field. It is easy to see why. At zero field the particles are free to move as they like. When a magnetic field is applied this is no longer the case since the particles are forced to align in a specific direction. The stronger the field, the less free the particles are to freely move, which translates to a viscosity change.Abiermans (talk) 10:04, 19 December 2007 (UTC)
thread_title: CSI: NY

message: I have provided a number of images which I believe to be higher quality and more informative than the ones currently used on the article. Feel free to make use of them. --Gmaxwell 01:19, 13 July 2006 (UTC)
replies: text: Whoa! — Omegatron 02:33, 13 July 2006 (UTC)
thread_title:  Take your pic 

message: Part of the article has been copied by  without respectng GFDL. Cruccone 23:37, 11 November 2006 (UTC)
replies: text: I don't speak Slovak. Using Babel, I've asked a Wikipedian who does to speak to the author of the website. --Eyrian 23:52, 11 November 2006 (UTC)
thread_title:  Copied 

message: We need something like     — Omegatron 05:35, 2 January 2007 (UTC)
thread_title:  Diagram 

message: Can I remove the tag?  It's really not a big deal. — Omegatron 05:36, 2 January 2007 (UTC)
thread_title:  How to section 

message: Slashdot recently linked to an article that prominently linked to this page on Wikipedia so keep your eye out for vandals. --⁪frothT C 07:43, 4 January 2007 (UTC)
thread_title:  Possible vandalism alert 

message: This is very confusing to me.  First it is stated:
Ferrofluids are composed of nanoscale ferromagnetic particles
Later we read:
Ferrofluids have numerous optical applications due to their refractive properties; that is, each grain, a micromagnet, reflects light
When I link to the micromagnet hyperlink, I am taken to the article on magnets.  So the second quote is saying that ferrofluids are composed of particles, each of which is a magnet.  That is, each particle exhibits a magnetic moment (I guess is the way you say it) without an external magnetic field being applied.  But if that is true, why is the first quote "Ferrofluids are composed of nanoscale ferromagnetic particles" and not "Ferrofluids are composed of nanoscale magnetic particles"? —The preceding unsigned comment was added by 4.238.240.56 (talk) 08:51, 18 February 2007 (UTC)
thread_title:  Clarification needed 

message: How/When/Why was Ferrofluid developed and by whom?  Answer that question and this will be a better entry --CPQD 00:45, 25 February 2007 (UTC)
thread_title: History

message: This is just an idea, but someone might want to increase the size of the pictures on the topic page, by a little bit. 
Tell me if you want me to do it. --•Tbone55•(Talk) (Contribs) (UBX)  (autographbook)  20:44, 25 February 2007 (UTC)
thread_title: Idea

message: Would this make the particles freeze in their new alignment? making the fluid a ferromagnet as long as it was frozen? I'd guess so, cos it would be like the heat and beat method of making iron ferromagnets.  Does anyone know for sure? Tom Michael - Mostly Zen  (talk) 22:39, 25 February 2007 (UTC)
thread_title: What if you Froze a ferrofluid whilst the magnet was present?

message: These surfactants serve to decrease the rate of ferroparticle settling, of which a high rate is an unfavorable characteristic of ferrofluids. The ideal ferrofluid would never settle in the absence of real-world friction. Surfactant-aided prolonged settling is typically achieved in one of two ways. In the case of the addition of soy lecithin, the surfactant particles are nanospheres and prolong the onset of settling via Brownian motion. In the case of oleic acid and other micelle surfactants, the effective diameter of each ferroparticle is increased by the attachment of micelle molecules to each ferroparticle, thereby increasing particle diameter and making fluid remixing (particle redispersion) occur far faster and with less effort.
I think the information above is not correct. Making a stable ferrofluid requires solving of two problems. The first problem is settling of the particles in a magnetic or gravitational field. This problem is solved by making the magnetic particles very small, typically 10nm or smaller so that they can be kept in suspension by Brownian motion. The second problem is clumping together of the magnetic single domain particles, these particles are magnets afterall. That problem is solved by coating the particles with a surfactant. Steric repulsion prevents the particles from agglomorating. The surfactant addition has nothing to do with settling in the way it is described. This should be changed in the article. I am not sure I am comfortable editing the article.Abiermans (talk) 22:21, 12 December 2007 (UTC)
thread_title:  Role of surfactant in a ferrofluid 

message: In fact, ferrofluids display paramagnetism, and are often referred as being "superparamagnetic" due to their large magnetic susceptibility.
Ferrofluids are not referred to as "superparamagnetic" because their magnetic susceptibility is large. They are "superparamagnetic" because they exhibit paramagnetic behavior even when at temperatures below the Curie or the Néel temperature. At least this is my understanding of ferrofluid behavior.  —Preceding unsigned comment added by Abiermans (talk • contribs) 23:28, 14 December 2007 (UTC)
replies: text: I rewrote the paramagnetism page but I am not quite sure how to include this. I think there is a big problem in nomenclature here. Maybe the macroscopic response of a ferrofluid can be called (super)paramagnetic, but can the material be called that? Surely within each single domain the thing is ferromagnetically ordered! I think the statement ferrofluids display paramagnetism is incorrect. Ferrofluids display superparamagnetism and then explain that the latter requires ferro-ordering at the domain level, I'd think.
Jcwf (talk) 01:14, 1 January 2008 (UTC)
thread_title:  paramagnetism versus superparamagnetism 

message: All nano-particles are sub-microscopic. Someone chnge this please, it's redundant.  —Preceding unsigned comment added by 24.86.253.202 (talk) 20:21, 15 December 2007 (UTC)
thread_title:  Needs Fix 

message: someone explain why this occurrence is so......uniform in appearance please.  —Preceding unsigned comment added by Murakumo-Elite (talk • contribs) 08:29, 29 January 2008 (UTC)
replies: text: From what little I know, the peculiar shapes are caused by the liquid's reaction to the magnetic field lines. 71.113.22.132 (talk) 06:21, 2 March 2008 (UTC)
thread_title:  the shape and nature  

message: Oleic acid does not usually act as a surfactant unless it is saponified. So is oleic acid correct, or should it read "saponified oleic acid?" Rees11 (talk) 16:23, 22 March 2009 (UTC)
thread_title:  Surfactants again 

message: Magnetic viewing film is NOT in any way related to ferrofluid, and the reference should be removed.
"It is a translucent thin flexible sheet, coated with micro-capsules containing nickel flakes suspended in oil"
Nickel flakes are not nano-scale matter and is misleading and confusing for the reader.~~Pinestone 10:48, Sept 24, 2009 (EST)~~
:You seem to have misunderstood the purpose of See also sections:  They're purely for navigation purposes, not content.  Readers of this article might reasonably be expected to have an interest in reading one or more of the articles listed there; therefore, someone listed the article in See also.  No direct connection is implied or expected as a result.  WhatamIdoing (talk) 03:41, 30 September 2009 (UTC)
replies: text: If you want to adjust a disputed point in an article, an assertion is not sufficient.  Please provide references to substantiate your point.  WLU (t) (c) Wikipedia's rules:simple/complex 10:26, 30 September 2009 (UTC)
thread_title: Please note: incorrect reference

message: The sentence below sounded wrong to me so I will change it. Shouldn't the Curie temperature of a ferrofluid be independent of the carrier liquid and surfactant?
"However, ferrofluids lose their magnetic properties at sufficiently high temperatures, known as the curie temperature. The specific temperature required varies depending on the specific compounds used for the nano-particles, surfactant, and carrier fluid."
Electricmic (talk) 05:06, 22 October 2009 (UTC)
thread_title: Curie temp

message: I think Brownian Motion is a red-herring in this discussion. Even if there were no such thing as Brownian Motion the steric repulsion of the micels would keep the nanoparticles in suspension. Also, a strong magnet pulls the magnetite with forces far greater than the gravitational weight of each particle. "Weight" is another red-herringin this discussion. Who will word-smith a better paragraph than what we currently have (below)?
"These surfactants prevent the nanoparticles from clumping together, ensuring that the particles do not form aggregates that become too heavy to be held in suspension by Brownian motion. The magnetic particles in an ideal ferrofluid do not settle out, even when exposed to a strong magnetic, or gravitational field."
Electricmic (talk) 13:10, 22 October 2009 (UTC)
thread_title: Brownian Motion

message: It was in the movie Jennifer's Body (2009), when Jennifer just became a daemon and vomited a blacky 'evil'.  —Preceding unsigned comment added by 151.72.35.57 (talk) 09:10, 30 January 2011 (UTC)
replies: text: Are you claiming that this is a reference to ferro-fluids in modern culture or something?  (Ferrofluids are often black and move oddly in the presence of magnetic fields).  I kinda doubt it - and it certainly doesn't rise to the level of needing to be mentioned in this article. SteveBaker (talk) 14:58, 30 January 2011 (UTC)
thread_title:  Jennifer's Body 

message: Could someone please add a History Section to this article, better explaining the HISTORY of Ferrofluid? Thanks! Don't forget the sources.  — Preceding unsigned comment added by Doubledragons (talk • contribs) 17:58, 9 March 2012 (UTC)
replies: text: Some (admittedly brief) investigating only yields that ferrofluid was "discovered in the 1960s at the NASA Research Center, where scientists were investigating different possible methods of controlling liquids in space." I can't find the names of any researchers involved, any records of the experiment(s), the exact year, or anything else. This small amount of information seems difficult to incorporate into the article without more details. MosmordeanCreed (talk) 03:09, 8 May 2013 (UTC)
thread_title:  History Section 

message: I am going to remove the equation on the resistance of a ferrofluid. For your reference, the equation as it is currently is shown below:
There are a lot of problems with this formula. Most pressing is that I can't find a legitimate scientific reference for an equation for the resistance (or probably more accurately the resistivity) of a ferrofluid, and I can find no data on the Vollema Value or Pietrow constant that isn't clearly copied word-for-word from this article. 
Another issue is that this equation is extremely poorly mathematically expressed. The argument of an exponential should be dimensionless, yet in this formula it clearly has dimensions of mT^2. The Vollema Value is very undefined, though I assume it is a value in mega-ohms. However, the Pietrow constant as far as can be identified from the article, appears to be a dimensionless number, which is nonsense! You can't add two dimensionless numbers (or mega-ohms and a dimensionless number) and get mega-ohms! 
Because all these issues with this formula are so egregious, and since it appears that this formula has already been blindly propagated to other sources on the web and has been misleading high school students: http://www.slideshare.net/sunjerry019/ferrofluid-v2-9117602, http://www.thescienceforum.com/physics/25051-vollema-value.html, I am going to delete it. If someone finds it necessary to re-introduce this formula (cleaned up), they can use the quotation above as a reference.
Tevye guy (talk) 10:04, 25 April 2014 (UTC)
thread_title:  Removing equation on resistance of a ferrofluid 

message: There should be a more thorough description of normal-field instability because it is a little confusing.  — Preceding unsigned comment added by Ihsanturk (talk • contribs) 20:01, 20 March 2016 (UTC)
thread_title:  Normal-Field Instability 

message: There is an image in this article with the caption "Ferrofluid is the oily substance collecting at the poles of the magnet which is underneath the white dish." - however, no "white dish" can be seen in the image. If there is indeed a "white dish" in the image, more information needs to be provided in order to discern it. But I get the feeling the image is simply mislabelled, seeing as the ferrofluid is in fact front-and-center in that image, not just "collecting at the poles of the magnet". I could be totally wrong though as I know next to nothing about this subject, it's just something I noticed in passing. Cheers. 124.176.54.64 (talk) 06:45, 7 June 2016 (UTC)
thread_title:  Image caption 

message: The following lacks sourcing, or independent sourcing that would show that the content is WP:DUE.  Moved here per WP:PRESERVE. Per WP:BURDEN please do not restore without finding reliable, independent sources, checking the content against them, and citing them.  thx
;Art
Some art and science museums have special devices on display that use magnets to make ferrofluids move around specially shaped surfaces in a fountain show-like fashion to entertain guests. Sachiko Kodama is known for her ferrofluid art.
The Australian electronic rock band Pendulum used ferrofluid for the music video for the track, Watercolour. The design house Krafted London was responsible for the ferrofluid FX in the video. The post-metal band Isis also uses a ferrofluid in the music-video for 20 Minutes/40 Years.
Martin Frey, a German designer and technologist, built the pixel-based ferrofluid display SnOil in 2005. The device consists of a 12×12 matrix of electromagnets, allowing the apparatus to display text and run simple games.SnOil - A Physical Display Based on Ferrofluid. freymartin.de
CZFerro, an American art studio, began using ferrofluid in its productions in 2008.  The works consist of ferrofluid displayed in a unique suspension solution.  These works are often used as conversation pieces for offices and homes.
-- Jytdog (talk) 18:19, 26 April 2017 (UTC)
thread_title:  unsourced 

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thread_title:  External links modified 

message: Are surfactants too magnetic like opposite poles attract and vice versa. 103.210.50.152 (talk) 06:35, 13 January 2022 (UTC)
thread_title:  Ferro fluid 

message: Your wiki don't begin with latest discovery or get people stuck in it till they answer the next step. 103.210.50.152 (talk) 06:37, 13 January 2022 (UTC)
thread_title:  Latest discovery 

message: Can someone make the introduction a bit less technical? Noel Malik (talk) 19:23, 29 January 2023 (UTC)
thread_title:  SUGGESTION