Anyone know things about anodizing assemblies?

I have a part that I am developing that would be best constructed by pressing a stainless insert into it, then continuing to machine the part. (one wearable passage inside a manifold) the part ends up hard anodized. Does anyone know what happens if you hard anodize 6061 with stainless in it?

Thanks!

-Parker

This will not work. You will need to remove the insert before you anodize. If you need an insert titanium, or perhaps a hard plastic like phenolic will work.

The only metals that can go inside of the anodizing tank is aluminum and titanium. Lead can be used as the cathode (positive terminal), but if there are any inpurities in the lead, there will be problems.

Anodizing fluid is simply dilute battery acid (Sulfuric). Iron in the steel will get into the solution (as ions?) and mess with the anodize. In short...funny things will happen.

It also has to be watertight. If any acid gets between the parts, it will leak out afterward and ruin the hardcoat.

There is a slim, (very slim) chance that it may be possible to mask off the insert. The anodizing shop would have to see the actual part to determine if it is doable.

The insides of the passages is the part that needs anodized the most, I will just have to go with a Ti insert.

Thanks a bunch for the help!

By the way, what happens when you anodize Ti pressed into aluminum?

The insert will mask off the aluminum so it will not be anodized. If you are trying to anodize the passage to provide a bit of wear abrasion you will need to remove the insert prior to anodizing.

I don't need the aluminum anodized underneath the Ti... That's the point, the Ti is protecting the aluminum. Not the anodize.

Imagine a square block. The existing prototype has a hole drilled one direction to the middle, and another direction 90 degrees off of that. The gas in the manifold is eating out the material where it is making that 90 degree turn. I am going to bore and press fit a piece of Ti down the line of one of these holes. Then drill the Ti the one direction, and drill into the end of that Ti- hole the other direction, so that the 90 degree turn is made in the Ti. I have no need for the aluminum under the Ti to be anodized. The question is if the ti and aluminum will be fine getting anodized at the same time, since pressing a dowel in, and drilling it would be best done while the entire part is machined, instead of after the anodization is done, and the part can get nicked up before going to market.

-Parker

Sorry about the misuderstanding. I have a couple devices I developed that use anodizing as a method of providing some degree of abrasion protection and thought that you might have a similar application.

Yes the aluminum and Ti will be fine getting anodized at the same time. As mentioned above, if the acid gets trapped between the insert and part, it could come out anddamage the anodize layer. This will be especially evident if the part is dyed as the color will look streaky.

Ti is normally used as the rack/basket/wire to hold the aluminum in the bath while it is being anodized. You can use an aluminum rack/basket/wire to hold the part in the bath, but it gets anodized too. Then you have to throw it away or put it in a 'stripper bath' to get rid of the anodize. With Ti you don't have to strip it.

No worries, Yeah, I'm hoping the Ti will act as a 'thicker anodized layer' since you can't anodize selectively, and can't get thicker than a few thou anyway. in teh rest of the part the hard anodize is performing miraclously, but this one place where the gas makes a 90, it blows out. So, just sleeving it, basically... $3.00 fix.

(the customer thought they wanted to go Ti on the whole part... that wholesales in the $70 range. ahhh... business majors.)

-Parker

Titanium is easier to anodize than the aluminum is, and the process can be performed in the same sulfuric acid electrolyte. Depending on voltage, the titanium might turn crazy colors; be prepared.

I'm not sure what will happen at the Al/Ti interface. Should make for an interesting experiment.

Henry

Anodizing titanium is a totally different chemical process than aluminum. They are not even the same whatsoever. I have never anodized aluminum with titanium and am not sure what you would end up with. Aluminum anodizing basically creates a thicker usually porous oxide that is tougher than the aluminum alone and can be dyed colors in most instances and requires corrosive acidic chemical solutions to complete the electrolytic reaction. Titanium anodizing, as well as tantalum, niobium and a couple of other less notable metals is accomplished with simple DC voltage in a few seconds in a conductive solution of for example, water and a little bit of TSP. Titanium anodizes by exiting and causing the electrons in only the surface molecules of the metal to jump into higher orbitals therefore causing the material to reflect/absorb light from different parts of the light spectrum. Titanium anodizing does not add to the thickness of the metal nor is it more wear resistant to any real degree. Good luck with your project