Metal finishing Q&As since 1989
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Materials to coat invar?
1997
Q. Hi,
I am looking for a material to coat Invar. I have a small SiN ball that slides on an Invar flat plate and I would like to minimize the friction coefficient between the two surfaces. I do not want though to increase Invar's low coefficient of thermal expansion, thicken up more than .0003" Invar's surface and I would like to have a minimum 75 Rockwell Number.
Thank you in advance,
Kostas Zafiriou1997
A. Have you looked into coating the surface with CVD Diamond? Diamond has a coefficient of friction near to Teflon, but is one of the hardest materials available. There is a new CVD coating process now being employed utilizing laser enhancement which greatly improves the deposition rates of the process. Rates of 1 micron/second have been quoted with this process. It also allows the use of only carbon dioxide as the precursor for the carbon film. There may need to be post deposition polishing required to improve the surface smoothness and cut down on the friction. I also believe the process can be conducted at much lower temperatures than has previously been required, I am not sure whether this would upset the CTE of the Invar. One additional note, the process is performed at atmospheric pressure.
Ken Provancha1998
A. My feeling is that you can use Diamond like carbon. These layer should have a good adhesion to invar.
Jean-Pierre ReyalBlack coatings for Invar
2000Q. I am looking for information - technical, suppliers, etc. - on a reliable and robust black finish/coating of Invar
Mike A [last name deleted for privacy by Editor]- Richardson, Texas, USA
A. Are you allowed to plate something over it, like nickel, and then blacken the nickel? We used to put nickel, then black nickel, then oil rub on magnets for mechanical gyros. That was pretty reliable, for the application. Robust and reliable in what atmosphere, condition, place?
Tom Pullizzi
Falls Township, Pennsylvania
2000
Black oxide coating on Invar
Q. Is it possible to obtain a black oxide coating on Invar (63% Iron 36% Nickel)?
Thanks and best regards,
P. Cirese- Firenze, Italia 2003
Coating on Invar bolts to prevent spalling
Q. I am seeking a coating to be used on Invar bolts, which will be used to secure sections of a large mandrel together for autoclave curing of composite material. The coating is needed to prevent spalling of the Invar threads which occur when unscrewing the nut from the bolt after curing. The nut will be stainless or carbon steel, as its CFE is not a factor in mold operation. Is Low-friction Chromium useful in this regard? Please suggest alternative coatings that might be suitable.
Thank you,
Ed Maycomposite part molding - Sedro-Woolley, Washington, USA 2004
Coating Super Invar
2004Q. I am using Super Invar in a design that will allow a optical lens to travel vert. and hor. in there house. But I an not sure if there is a coating that can be placed on the surfaces to ensure that they will slide easily in the vert and hor planes. I am think something like a teflon coating but teflon in itself would not be a good choice. Can someone help?
Kenneth StebbinsR&D; laser company - Bedford , Massachusetts
2004
A. Very little info. What's the environment, temp, forces, expected life? Why would Teflon itself not be a good choice?
Guillermo MarrufoMonterrey, NL, Mexico
Need nickel electroless coating on INVAR
2006Q. I'm looking for a procedure to deposit electroless Nickel on small pieces of INVAR for aerospace mechanisms. I need also qualified suppliers. Any help on this topics is welcomed.
Elena F [last name deleted for privacy by Editor]Wear of Materials - San Martin, Buenos Aires Province, Argentina
Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)
November 4, 2009
Q. Dear colleagues,
I'd would like to know which finishings are compatible and appropriate for a part made from INVAR. I'd need low emissivity for the outer surface and high emissivity for the inner surface (? and black chromium?).
Thank you very much for your time.
Design engineer - MADRID, SPAIN
Black chrome plating of Invar 36 material is not uniform
July 21, 2015Q. I have some issues about black chrome treatment for Invar 36 material. After treatment the surface is not uniform. Anyone can help me, give me some information? Thanks.
(click thumbnails for higher rez photos)
product designer - Singapore
July 22, 2015
A. Hi Stefan,
Applying a slight tinge of oil will make the product look better. Does the presence of oil have any effect on the product?
- Penang Malaysia
November 6, 2019
A. You might try bead blasting before plating.
Julian HolmesEngineering - Wales UK
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