Chemical inhibition of pitting corrosion in methanolic solutions containing an organic halide

• Main Authors: McEachern, Heather, Garza, Timothy Z, Cook, Stuart Edward, Liu, Zhengwei, Panchaliangam, Vaithilingam, Ramachandran, Sunder, Thieu, Vu, Stead, Paul Robert, Rivers, Gordon T
• Format: Patent
• Language: English
• Published: 06.12.2018
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25; NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE

Pitting corrosion of stainless steel occurs in solutions of organic acid, such as tartaric acid, in an electrolyte solution with methanol. However, methanolic solutions containing at least one organic halide and at least one organic hydroxyacid and some water provide reduced 5 pitting corrosion of stainless steel. The organic hydroxyacid may be a hydroxy acid containing 2 to 10 carbon atoms with at least one hydroxyl group and at least one carboxylic acid group, in a non-limiting example, glycolic acid. The pH of the methanolic solution may range from about 3.5 to about 8.