Monitoring corrosion using visible light
- Vilupanur Ravi, Professor and Chair, California State Polytechnic University Pomona
- Thuan Nguyen, Professor, California State Polytechnic University Pomona
Corrosion is a phenomenon leading to the loss or reduction in functionality of metallic materials due to reactions with the environment. Several studies have documented the enormous economic costs of corrosion. Some estimates place worldwide losses due to corrosion at $ 2.2 trillion dollars which translates to about 3% of the world's gross domestic product (GDP). Corrosion can create havoc in today's heavily industrialized world, e.g., the collapse of bridges leading to loss of life, pipeline failures in the petrochemical industry, etc. Early detection of corrosion would be of great benefit in avoiding costly and possibly fatal failures. In this study, we examine the possibility of using visible light as a simple, non-contact probe to study the onset and progression of corrosion. White light, colored light emitting diodes (LEDs), and laser light were investigated as possible probes. A solar panel attached to a multimeter served as a detector. The current measured by the multimeter is proportional to the intensity of light emerging from the solution. The corrosion of steel samples in salt water and bleach solutions was investigated. We found that the broad spectrum white light was most effective in monitoring corrosion. As the corrosion event progressed, the light intensity dropped. This method has the potential to be implemented in industrial applications and allow for preventative measures to be deployed sooner in the cycle because of the early detection of corrosion of critical components.