Talk:Anodizing

Jargon
This article makes use of all sorts of metalurgy jargon which the reader is clearly expected to know. Perhaps some of it can't be avoided. In that case, said terms should be wikilinked.

I'm tempted to go in and wikilink them myself, but that's a slippery slope. It'd be better if someone who knows their stuff were to go through and decide what terms should be briefly defined in the article, and what terms should simply be linked to their respective articles. Dave314159 17:07, 4 April 2006 (UTC) I was disapointed that the number of seconds the electric current flows was not mentioned. Ccpoodle 04:38, 15 June 2007 (UTC)

Repetetive Redundancies
'I notice that an edit added "The pipes can accept certain dyes which provide a coloured finish." Given this is covered in the last para does this information add anything? It is repetition, but which should go and which stay? Ian 15:17, 26 Jul 2004 (UTC)

Doesn't greatly matter. I realised my mistake shortly after making it, byt had a loss of connectivity before I could get back to fix it. I have reverted my changes out. Rich Farmbrough 22:02, 27 Jul 2004 (UTC)


 * Chronologically, your place for the info. was better. But as it's less important than the actual process, having it separate seems OK. As you say, it doesn't matter than much. Ian'

What carabinders?
I can't get the caribiners picture to show up on the article. --Auric 04:48, 13 January 2006 (UTC)


 * I think there's a temporary server problem. —BenFrantzDale 04:58, 13 January 2006 (UTC)

Anodised Titanium
This seems to be quite Aluminium-centric. What about Titanium? -- Sy / (talk) 20:52, 11 May 2006 (UTC)

Doesn't the color also depend on the oxidation state of the oxide formed (TiO2 vs Ti2O3 etc.), just as solutions have different colors? Same for Niobium. — Preceding unsigned comment added by 165.222.184.132 (talk) 13:06, 22 November 2011 (UTC)

Anode (negative electrode?)
The article states that the aluminium is made the anode (negative electrode). I was under the impression that an anode was the positive electrode and the cathode the negative electrode. I think the aluminium is made the positive electrode (anode) as aluminium ions are Al2+ (?) so needs to be the anode. This is in order to be oxidised by the oxygen ions.

The anode is positive
I have just read the comment on the discussion page that points out that the anode is positive and the cathode is negative. This is correct. I don't know how to amend the article, but it should be amended to ensure that it is correct. David - UK —The preceding unsigned comment was added by 172.207.80.135 (talk) 14:51, 6 December 2006 (UTC).

I fixed it. Sorry it took so long. Thanks for making the entry on the talk page. Comfr (talk) 06:30, 23 December 2015 (UTC)

cold sealing
"Sealing at 20 °C in nickel-cobalt salts, cold sealing, when the pores are closed by impregnation is also popular due to energy savings. Coatings sealed in this method are not suitable for adhesive bonding."

Is cold sealing the name for any process with nickel-cobalt salts at 20 degrees? Should we say room temperature? Can I assume it can be just around 20 degrees? Maybe it's only called cold sealing when "the pores are closed by impregnation" and other times it's just nickel sealing? --Gbleem 02:29, 25 December 2006 (UTC)

"Anodization changes the microscopic texture of the surface and can change the crystal structure of the metal near the surface." Should I say can or does? Does it always change the structure of the metal layer? --Gbleem 02:54, 25 December 2006 (UTC)

Request for anodisation specialist review
Sorry for the off-topic post, but I have a hypothesis about anodizing aluminum with DNA that I've written up (perhaps not so clearly) at http://infoeng.sf.net/dic-proposal.pdf. I would be enormously grateful if anyone could provide me with any feedback regarding that paper. Thanks. :) JPatrickBedell 22:53, 11 February 2007 (UTC)

British vs. American Spelling
Not a big deal from a science standpoint of course, but jumping back and forth in spelling variants isn't ideal. Pick one or the other. The vast majority of references in the article and on the web are of the American spelling so I changed the rest in the article (may have missed a few) to match. I cannot figure out how to change the title of the article though. —The preceding unsigned comment was added by 128.120.179.12 (talk) 00:13, 24 February 2007 (UTC).

Moved page to anodizing --Readams 03:09, 11 March 2007 (UTC)

Note that you shouldn't have done this- pages are meant to stay at their original spelling. 124.171.130.134 (talk) 07:13, 12 June 2008 (UTC)


 * No they're not. Wikipedia is an editable encyclopedia. If we see something that needs to be changed, we fix it.--Yannick (talk) 10:58, 10 October 2009 (UTC)


 * I don't know about back in 2009, but today the article specifies the use of American spelling. Since some of the words use the British spelling, should I change them? --Trifler (talk) 03:10, 30 April 2017 (UTC)

Chemically bonded to surface
I removed a few statements which said the strength and adhesion of anodic films could be explained by the fact they are chemically bonded to the surface, or that they are grown on the surface. Paints, chromate conversion coatings, and arguably platings are also chemically bonded, but they crack and peel much more easily than anodic films. The reason for the greater strength of anodic films has to do with the fact that oxygen binds to metals better than anything else, and that most metal oxides like alumina are very strong by themselves, which is again due to the strong oxygen bonds. But I don't have a clean way to explain that, nor do I have references to cite.--Yannick 02:38, 20 May 2007 (UTC)

Hot Sealing process
I'm curious as to whether the hot sealing process (normally immersing in boiling water) is a chemical or thermal reaction/process - can anyone clarify for me? It is unclear from the main page.
 * Note that the dichromate seals are also hot processes. But I don't know the answer to your question.--Yannick 17:17, 6 October 2007 (UTC)

Process Specification Details
It looks like someone included too many or not enough zeros on some of the thickness specifications for MIL-A-8625. —Preceding unsigned comment added by 216.182.41.210 (talk) 13:29, 9 June 2008 (UTC)

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Factually accurate/inaccurate
As I read though this article, I come across some items that initially struck me as incorrect. Has an expert in the field looked this article over? A couple of areas that didn't seem right upon initial viewing include the descriptions of Types (I, II, and III), and the thickness for hard anodize that doesn't match the standard at all (.0020 +/-20%). Is anyone else noticing these sort of issues? —  f c s u p e r ( How's That?, That's How! ) (Exclusionistic Immediatist ) — 01:13, 27 November 2010 (UTC)


 * Is that the standard? Because commercially I find the tolerance to be around +/- 100%. LOL...but to answer your question I haven't reviewed the article. Wizard191 (talk) 02:29, 27 November 2010 (UTC)


 * Wizard191, according to the MIL spec, that is the standard. It is necessary to achieve the required hardness.  Also, I've striked-out my comment about types.  That part is correct (just checked). fcsuper (talk) 14:41, 27 November 2010 (UTC)
 * I think you mean the required durability. The coating is the same hardness no matter what thickness it is. Wizard191 (talk) 15:15, 27 November 2010 (UTC)
 * Yup. We can work on clarifying any issues with the article over time.  I think it is close enough right now to be OK without requiring any urgent edits.  —  f c s u p e r ( How's That?, That's How! ) (Exclusionistic Immediatist ) —  16:57, 27 November 2010 (UTC)
 * I agree. Removing technical tag now. Guy Macon (talk) 18:23, 19 March 2011 (UTC)

RoHS options
When I left Fluke Manufacturing in the mid 90's they had converted the Chrome(VI) anodizing of Aluminum to Chrome(III) Anodizing. Freshly cut Aluminum acquires a thin layer of Oxide when exposed to Air; Oxygen atoms diffuse into the Aluminum metal lattice so initial oxide is expanded metal lattice, some Al atoms attached to both metal and oxide. The oxide layer is strengthened by being under compression. Chromium(III) (slightly larger than Al atom) can replace Al atoms (e.g. Ruby) in Aluminum Oxide. The Fluke requirement was not only corrosion resistance but also electrical conductivity of the oxide to provide a good Ground for electrical parts inside the Aluminum cases. Uncontrolled oxide growth was implicated in fires caused by use of Aluminum wire cable for House wiring (ROMEX).

Paint does not passivate. Paint generally does not chemically bond with the Aluminum surface, but rather it is physically held by surface roughness. Aircraft from WWII on generally were left as shiny unpainted Aluminum. (The surface roughness of the paint used and the extra weight slowed aircraft down.) For commercial aircraft FAA requirements for surface inspection made stripping and repainting costly. Relaxation of FAA testing requirements led to more than a few crashes. We examined Aluminum skin of a crashed jet. Small scratches in the paint allow moisture and Chloride to penetrate, the rest of the paint surface becoming the cathode. The penetrated moisture and chloride are concentrated at a point, furthest from the scratch, which is the anode; the concentrated Hydrochloric Acid eating the oxide and underlying Aluminum becoming a stress crack locus. (The pressure cycling of 0 to 33,000 feet and back on many short hops did the rest, and the fuselage ripped open.)

Shjacks45 (talk) 04:27, 24 July 2011 (UTC)


 * Not sure what the point of this brain dump was, but several of these details are confused:
 * Fluke's chromate conversion coating is not the same thing as anodizing.
 * The "surface roughness" theory of paint has long been disproven. If it were true, then paint primers would have no effect.
 * "We found a scratch in the paint job, therefore our design's not at fault" is a common excuse in the aircraft industry.
 * --Yannick (talk) 14:59, 9 May 2012 (UTC)

Needs pictures of aluminum colors
I came here looking for the colors possible with anodized aluminum. Somthing like that strip on the titanium section but for aluminum would be great. --TiagoTiago (talk) 16:14, 17 February 2013 (UTC)


 * As the article says, the colors possible are almost limitless. They are achieved by adding dye, and there are lots of different dyes in the world.  The titanium chart shows the colors you can get without any dye.  Aluminum anodizing just looks like aluminum without any dye. Ccrrccrr (talk) 01:15, 11 February 2014 (UTC)

Marin County Civic Center
I think the Marin County Civic Center picture should be removed. It's not helpful in showing what anodizing looks like, especially without color, so it's really just there as trivia. Ccrrccrr (talk) 01:17, 11 February 2014 (UTC)

Aluminium radiators
I read that black anodised aluminium have very high emissivity compared to pure or alloyed aluminium, so this is why it is used for radiators. If somebody knows if it is true, please add this info. — Preceding unsigned comment added by 2620:0:105F:311:C16B:9E80:F90A:59E3 (talk) 11:34, 8 December 2014 (UTC)

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Aluminum history
The history section talks about when anodizing was first used in general. I'm interested in when it was first used on aluminum. I would also like to know when it was first used on a large scale specifically for dyeing. --Trifler (talk) 03:02, 30 April 2017 (UTC)

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Strange title / heading
The "Other widely used specifications" is weirdly placed there. "Other" than what? MarmotteiNoZ 20:01, 22 March 2024 (UTC)