KINETICS OF GLASS FIBRE CORROSION BY OXALIC ACID
Robert L Jones* and Cheryl L Rappa
Curtin University of Technology
The corrosion of glass fibres in acidic solutions has now been well established. The accepted mechanism is an ion exchange process involving the leaching of cations associated with the glass phase into the surrounding solution, and the replacement of these cations with hydrogen ions( ). This process initially causes stresses on the surface of the fibres which eventually leads to cracking and ultimate failure. Several catastrophic failures of Glass Reinforced Plastic materials have been reported which have been attributed to this corrosion process. It appears that the nature of the anion associated with the hydrogen ion has a major influence on the corrosion process as well as the actual hydrogen concentration itself. Oxalic acid has emerged as the most corrosive agent to date on account of its ability to form complexes and insoluble salts. Studies to date have been mainly confined to room temperature and no attempts have been made to relate the corrosion process to temperature. This work investigates the corrosion of glass fibres by oxalic acid over a series of temperatures in an attempt to understand more about the kinetics and energetics of the corrosion process. Corrosion is less severe at low temperatures but very rapid at temperatures above room temperature.