Metal finishing Q&As since 1989

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Are plated and polished metals ready for solar concentrators?

We have used glass mirrors with mechanical backing (usually metal, or a composite honeycomb) for our Solar Collectors, but would now like to explore the use of other materials, such as plated metal or other base material. The hitch has been that these combinations always offer less reflectivity than required. Many changes have occurred in the solar industry over the last 5-10 years, and it's time we re-examined this subject. What is the range of reflectivity that we can now expect with plating and polishing? For the right combination of cost and weight, there is almost no value that is unacceptable for all situations.

Don Kesner
Solar equipment manufacturer - Phoenix, Arizona, U.S.
2004

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You are right, it is time to revisit this questions. Recent advances in thin film processing and high speed electroforming developed for the projection TV market make it now possible to manufacture high performance thin film overcoated optical quality metal reflectors that can withstand > 350 ° for > 4000 hour. For example an enhanced Al coated electroformed Ni or stamped stainless reflector can have reflectivity > 94% in the visible.

The only problem is that there has to be the correct business demand (volume and pricing) behind it to justify a multi million dollar infra structure investment.

Karlheinz Strobl
electroforming and thin film coating - Bohemia, New York
2004