Cobalt chrome etching process

Abstract

Compositions and methods for etching cobalt chromium alloys are disclosed. The compositions generally include at least two mineral acids, certain component metals of the alloy to be etched, and optionally iron (Fe). For example, when etching a cobalt chromium molybdenum alloy, the component metals may include chromium (Cr), molybdenum (Mo), and optionally, cobalt (Co). The at least two mineral acids may include hydrochloric acid (HCl), nitric acid (HNO3), and hydrofluoric acid (HF). The methods provide for etching an entire surface of a substrate or etching a surface of a substrate in a pattern using selective coating patterns and/or coating removal. Thus, unlimited patterns, as well as etch depths and variations in etch depths are achievable using the compositions and methods disclosed. Moreover, the compositions and methods provide cobalt chrome surfaces having very low surface roughness (Ra) that are useful in the aerospace industry.

Dependencies are inferred from the claim text.