PHOTOCHEMICAL ETCHING OF METALS

摘要

Wet chemical etching of metals has been practiced for hundreds of years. Initially, the metallic substrate was cleaned as well as possible to promote adhesion of the maskant and retard undercutting during etching, then a strongly adhering, etch-resistant maskant was applied, usually by dip coating or by brush, and cured. The desired pattern was then carefully scraped away, exposing the metal to be chemically removed. After the etching was completed, the remainder of the maskant was removed and the required finishing operations were done. Typical maskants were resins, waxes, bituminous-based materials, and other natural materials. Today, maskants are commonly called resists, probably because the maskant resisted the etchant. Various acids were used as etchants. The resulting products were only as good as the artists who removed the maskant providing the pattern and the skill of the etcher. Successful etching was an art whose secrets were carefully guarded.