What is Ebonol C? 1

[billtati]

My company manufactures electronics rated for space applications. We are considering using a vendor supplied heatsink that has the following finish "Black Ebonol C". I have been unable to find documentation of this finish in regard to any industry standards (MIL, ASTM, etc) that cover such a finish. I would like to determine what standard this finish meets, exactly what it is composed of, and is it approved for space applications (low outgassing, TML, etc)?

Thank you in advance for any assistance you can provide.

 

[kenvlach]

Ebonol C is a chemical blackening process for copper. The Metal Finishing Guidebook shows Enthone-OMI as the supplier. However, I could not find it on their website. Suggest contacting them for more info:

http://www.enthone-omi.com

Some otther companies with similar products:
EPI has Ultra-Blak 420

http://www.black-oxide.com/hot-oxide-blackening.html#420

Heatbath has Durablack

http://www.heatbath.com/Products link page.htm

The only applicable MIL spec. is MIL-F-495E FINISH, CHEMICAL, BLACK, FOR COPPER ALLOYS available form the ASSIST site:

http://assist2.daps.dla.mil/quicksearch/basic_profile.cfm?ident_number=2301

Pretty sure no ASTM spec. Probably no SAE spec. either, although conceivably it could fall into the alternative coatings category in the following:
AS4984, May 1999. Title: Coating Requirements for Aerospace Hand Tools. This SAE Aerospace Standard (AS) covers requirements for nickel-chromium coatings, black oxide or black phosphate coatings, and alternate coatings for aerospace hand tools. Classification: Coatings covered by this document shall be of the following types, as specified: Type I (nickel-chromium coating); Type II (black oxide or black phosphate coating); Type III (alternate coatings, used in lieu of nickel-chromium plating).

MIL-F-495E only requires the coating to withstand 2 hours of hot (195 F) soap solution or 200 hours water spray. These blackening coatings are normally laquered, oiled, or waxed for better corrosion protection and gloss. Omit this supplemental coating for space applications to avoid outgassing, for better heat loss and because many organics are unstable under solar radiation in space.

 

[kenvlach]

Forgot to add, Black anodized aluminum has NASA approval. Don't have the details, looked into it about 6 years ago. There was only one approved black dye at that time.

 

[billtati]

Thanks kenvlach. Some more information I was able to get from Enthone: There are two type of Ebonol C, the first is "regular" Ebonol C, the second is Ebonol C Special, which is used primarily as a primer for painting. This second type meets MIL-F-495, the "regular" type does not. The Enthone tech rep was unable to truly give a difinitive yes or no to low outgassing for space applications, and I was unable to find Ebonol C listed on the NASA site

http://outgassing.nasa.gov/.

The tech rep emailed me a data sheet for the finish, but this still leaves me not knowing if I can use parts coated with Ebonol or not. Anyone else have additional info or experience with this?