DIFFUSE, NON-SPECULAR REFLECTIVE COATING/PLATING (GOLD?)
Q. We are trying to coat a thin (.003 in) stainless steel part with a diffuse reflective coating. We only need 85-90% reflectance, but it must be largely lambertian. We have tried plating with 30 micro-inches of gold, but the resulting surface is too specular. These are photo-etched parts, and no particular surface finish was specified, other than the etchers standard clean-up, and whatever prep work the plater does. I am told that a matte finish can be achieved by post baking the parts, but have no idea how to specify same. The reflecting is in the near infra-red (810 nm), which is why we tried gold.
At this point I would welcome ANY suggestions.BOB PARKER
CyberOptics - Minneapolis, Minnesota, USA
A. You must polish the parts prior the plating and bright them after plating to get your desired results.
A. You need to specify the finish to be achieved before plating, either to be performed by the shop doing the plating, or by another operation in your own shop. You cannot let the plater decide how the part will be finished.
If you have a question in mind which seems off topic, please Search the Site