Reflective Metal Coatings
Abstract
Over seven hundred specimens of cold rolled or stainless steel have been coated with selected plastic formulae consisting of the general species polyurethanes, epoxies and silicones. Coating by the dip technique has been found most satisfactory. Of the 700 specimens over 150 have been coated with films of gold, copper, silver or aluminum and values of the relative reflectance, adherence and radiation absorption of the films have been measured. The relative reflectances, measured with a photometer over the wavelength region of approximately 0.5 to 2.5 microns and indicated as the relative reflectance of the specimen to that of a gold coated glass standard, have been shown to compare favorably with similar films respectively deposited on glass. The relative reflectance of silver films on polyurethane substrates was highest and the relative standing of the other metals in descending order was copper, gold and aluminum. The relative reflectance of a given metal varied with the type of plastic coating on which it was deposited in the descending order polyurethane, silicone and epoxy. Typical relative reflectance values found for gold on each material respectively were 0.96, 0.86 and 0.84; the value on glass was 0.995. Adherence measurements, made by a headed pin technique, revealed that the order of adherence was reversed from that of the reflectance, i.e., adherence values were in the descending order aluminum, gold, copper and silver. Adherence of the metal films to the epoxy, Maraset 617-C, was superior to that to polyurethane coatings. Films of aluminum passed the "scotch tape test" when deposited on epoxy or silicone coatings but did not perform as well on polyurethane. Gold films adhered well to the epoxy, Maraset 617-C. When the film adherence value was above approximately 550 psi the film normally would pass the scotch tape test.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1960
- Accession Number
- ADA451821
Entities
People
- M. D. Carithers
- R. B. Belser
Organizations
- Georgia Tech