Test results for a capacitance-based corrosion sensor

This paper describes a way of monitoring for steel surface corrosion in its early stages, before it becomes structurally dangerous. It is envisaged that the presented technique is used repeatedly across the surface of a large structure to monitor for structural danger. This widespread monitoring could be achieved by means of a distributed wireless sensor network, with each sensor reporting to a base station which then checks for indications of corrosion from sensors that are located near to each other, or that are all located on the same joint. In this way, potential structural problems can be monitored, evaluated and mitigated at an early stage. The sensor developed in this project is small, inexpensive and has low power requirements. It is therefore suitable to be integrated into a wireless distributed sensor array which could be set up and left to monitor autonomously for corrosion without human intervention. Current corrosion sensing technology is appraised before the theory behind a capacitive sensor to detect surface corrosion is presented. The sensor was then fabricated, and initial tests are detailed and the results discussed