Zinc Chromate and Vacuum Effects

[aaron28]

Hey everyone

I am having an issue. I work with vacuum furnaces and recently had a powertrack completely breakdown. I am looking to get a new track. The original plans call for an uncoated gleason powertrak; unfortnately Gleason coats their links with a Zinc Chromate. My question is, would this Zinc Coating effect my furnace pulling vacuum? If so, how hard would it be to strip this coating off of the links?

I can get the links uncoated from Gleason, but it almost doubles the price, and I need to replace 3 of them. Any insight would be awesome!!

 

[btrueblood]

Well, assuming your vacuum is fairly high (< a few Torr) and the temperature is above a few hundred deg. C, then yes the zinc will tend to evaporate off the links and onto the oven walls and whatever else is in it. There is data for the vapor pressure of zinc (and other metals) in the CRC handbook.

 

[aaron28]

Vacuum is low. It will never go positive, but it's more of the heat issue. Once started I will end up with outgassing. I was hoping that someone else encountered this issue with either links or even using coated bolts/nuts inside their furnace. Based on what I have read, and what others have said, looks like I will have to do a cost analysis of either getting coated stripped, or just buying the uncoated. Thanks for the info tho.

-What's the Difference between Mech. Engs. and Civil Engs?

-Mech create weapons, Civil create targets.

 

[MintJulep]

Generally zinc is not desirable in a vacuum environment.

Some manufacturers offer cable carriers nominally of stainless. But be careful of pins and bushings.

Igus makes a vacuum service rated carrier out of some sort of plastic. Not sure of its temperature limits.

 

[aaron28]

I am gonna check out Igus. I hate being stuck with one type of manufacturer. They can hold you over the furnace so to speak.

-What's the Difference between Mech. Engs. and Civil Engs?

-Mech create weapons, Civil create targets.

 

[EdStainless]

We used to acid clean components before they went into our furnace.
Even modest temperatures cause things to happen.

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P.E. Metallurgy, Plymouth Tube