Summary for black copper coating Discussion
Black copper coating for camera baffle parts is discussed as a way to reduce stray light and achieve very low visible reflectivity. Dr. T.K. Alex asks whether nickel vanes can be blackened and whether the process should be chemical, electrochemical, or vacuum-based. Dan Brewer says hot black oxide on copper is common and should meet the need, noting that black oxide is also used on internal camera steel parts. Russell Richter adds that the baffles would first need a copper plate about 0.0005 inches thick, then be oxidized with a proprietary oxidizer. Michael Brewington describes a real job on brass camera apertures: cyanide copper plating followed by a copper blackener, with a proprietary blackener also available for nickel, though the finish was powdery and had to be lacquered. A later reply recommends Acktar Magic Black, claiming total reflectance below 0.8% at visible wavelengths and applicability to copper and other materials.
Q. I have a requirement for black coating of Thin vanes of Nickel used in a camera baffle used to avoid stray light. The coating should have reflectivity less than 1.5 % in visible light. Base coating of different material is allowed.
Suggest a good coating method. Copper black on Nickel is known as a possible candidate? What is the process for such a coating? Is it to be done by chemical methods, electro-chemical method or vacuum evaporation?
Dr.T.k.ALEX
– Bangalore, Karnataka, India
A. Hot black oxide on copper is very common and should meet your requirements. Many internal camera parts are black oxide finished steel also. Hope this gets you going in the right direction.
Dan Brewer
chemical process supplier – Gurnee, Illinois
A. The baffles would need to be plated with copper approx..0005 inches thick and then oxidized with a proprietary oxidizer.
Russell Richter
– Danbury, Connecticut, USA
A. I worked on exactly such a job a few years ago. The parts were brass apertures for video cameras. We cyanide copper plated them and used a copper blackener. There’s also a proprietary blackener for nickel. The job was difficult because the blackening process left a rather powdery deposit that the customers complained about. So, we had to lacquer the parts too.
Michael Brewington
– Salisbury, Maryland, USA
Q. I am a student doing a literature review on black copper coating. I need to contact some companies but unfortunately I haven’t been able to find one in Europe that do black copper coating. Could you give some names or references of companies?
Vincent Arnaud
– Compiegne, France
A. I recommend you try Acktar Magic Black TM — this coating has total reflectance of less than 0.8 % at VIS wavelength.
It can be done on copper and other materials.
Dina Katsir
Acktar – Kiryat Gat, Israel
June 14, 2012