Colored conversion layers on metallic substrates

摘要

A chromium-free treatment solution for producing colored or fluorescing corrosion prevention layers on metal surfaces which contains phosphoric acid and/or at least one fluoro acid of one or more elements from the group consisting of B, Si, Ti, Zr and Hf or anions thereof and at least one organic polymer, the organic polymer being capable of binding to the metal surface through oxygen and/or nitrogen atoms, and having covalently bonded groups which appear colored to the human eye or which fluoresce discernibly to the human eye on exposure to UV light.