Senior corrosion engineer, Teledyne Wah Chang, Albany, OR
Zirconium and its alloys are well known for their corrosion resistance in a broad range of inorganic and organic media. They have played a key role in advancing the production technologies of urea and formic, acetic, hydroxyacetic, lactic, and methacrylic acids, methyl methacrylate, rayon, alcohols, and phenolic resins, etc. Laboratory data and case histories are used to demonstrate the advantages of zirconium and its alloys. Compared to other engineering alloys, the use of zirconium and its alloys allows producers to make products of high quality by operating processes at higher temperatures/pressures for improved efficiency and yield. Unlike many metallic ions, zirconium produces colorless ions. Most transition metals produce ions of different colors depending on their valence state. An increasingly important advantage is that zirconium appears to be nontoxic and biocompatible.
Limitations of zirconium and its alloys in organics are also discussed. They may be vulnerable in certain organic halides, such as acetyl chloride, that are incompatible with water. In water-soluble organics, such as methanol, water is necessary to inhibit localized corrosion. There are impurities, such as copper ions in acetic acid, that are undesirable for zirconium and its alloys. Control measures, such as water addition and stress relieving, can be applied to zirconium equipment in certain extreme conditions.
Paper ID: JTE12684J