-- The Home Page of the Finishing Industry
     No Pop-ups! No Spam!
HomeFAQsBooksHelpWantedsForum  ltr 2063

Serious Education ... plus the most fun you can have in metal finishing.

Blackening Copper


I have a copper panel that is kept at liquid nitrogen temperature when used in a vacuum system. One of it's purposes is for heat removal. There are indications that copper is a very good reflector of infrared radiation and thus a poor absorber. I am looking to increase the absorbsion of IR possibly by blackening the copper. I have heard that this can be done electrolytically. Is this true? Can it also be done by wiping liquid over the surface much like blueing steel (i.e., does it come in a bottle or do I have to send out the whole panel?)?

I also have some concerns about whether the 'blackened copper' will cause great problems in a production vacuum system like outgassing, flaking, etc.

Any other comments are always appreciated.

John Davis
- Berthoud, Colorado, USA



Try an immersion blackening liquid with copper panels: 1.6 - 1.9 g/L liverof sulfur or liquid polysulfide solution at around 25 C for 50 to 80 seconds. As long as you optimized the conditions to get the color you want, you can blacken your parts.

Good luck!


Ling Hao
- Grand Rapids, Michigan


Dear John ,

The solution offered by Ling is correct for blackening copper , however I suspect that because it is a simple conversion coating there might be problems with the adhesion , if you are looking for a coating that is black and adherent , then I would be looking towards Black Chrome Plating , provided the panels are not subjected to a lot of flexing and that the temperature can be GRADUALLY decreased then it may work

best regards

John Tenison-Woods
John Tenison - Woods
- Victoria Australia


What substance is produced when granular copper and sulfur are heated in a test tube? Thanks, Trisha

Trisha Fade
Albany, New York


Why do I get the feeling that this is your homework question, Trisha, that you would know the answer to if you had read the assigned chapter? It would depend on the atmosphere in which you did this. In a vacuum you could produce nothing but sulphides of copper.

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It is not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & DevicesUsed & Surplus

©1995-2016     -    Privacy Policy
How Google uses data when you visit this site.