Buffered Citrate Anodization Bath
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
A buffered citrate anodization bath useful for anodizing niobium and other metals, such as aluminum or tantalum, is disclosed. The buffered citrate anodization bath comprises a mixture of citric acid and sodium citrate in deionized water. An example of such a bath having a pH of 4.1 is a mixture containing 0.25% citric acid and 0.25% sodium citrate by volume. By varying the ratio of citric acid to sodium citrate, it is possible to obtain any desired pH in the range 2.5-8.0. By selecting the proper pH, chemical attack on other metals, photoresists or various plastics which may be in contact with the bath are minimized. The buffering action also makes the bath less susceptible to dilution effects or to acidic or basic components leached from these materials.