New Defect Sensor Promises to Keep a Careful Watch on Corrosion Beneath the Surface

A team of researchers from Bournemouth University and Oman's Global College of Engineering and Technology have developed a new sensor that, they claim, could help detect defects in structures from bridges to aircraft before they become a problem — acting as an early warning for corrosion damage.

"Our doctors often encourage us to take health screenings regularly, so they can diagnose conditions at an early stage which gives us better options for treatment," explains Zulfiqar Khan professor and project lead, of the work. "This sensor works on the same principal. If we can spot health risks in vehicles and mechanical structures before corrosion reaches an advanced and dangerous stage, we can avoid costly, lengthy repairs and hopefully prevent structures from being scrapped altogether."

Designed to replace traditional wired corrosion sensors, the team's defect sensors can be used wirelessly — and, in contrast with rival designs which work only when connected to sufficiently-conductive metal surfaces, can be attached to almost any material. It also boast the ability to peer "several millimeters" below the surface of materials, allowing for defects to be found which would be missed during visual inspection.

The sensor, which comes out of a series of research projects launched at the Bovington Tank Museum more than a decade ago, uses a special magnetic aluminum compound, AlₙXₙ, designed to be both highly conductive and sensitive to corrosion. Once constructed, the cells of the sensor are completely sealed — meaning it can be deployed in any orientation — while two can be used in tandem to perform non-destructive testing of material coatings.

"Unmonitored failures lead to costly consequences. Scheduled inspections are tedious, time consuming and are mostly limited to visual or surface failures," Khan claims. "Our latest sensor technology is a futuristic, much needed solution. It can work remotely, it works on metallic and non-metallic surfaces and can detect defects several millimetres below the surface which are not visible to the naked eye."

The team is particularly interested in seeing its device used to monitor vehicles and structures in storage which are not regularly inspected — such as those found in the Bovington Tank Museum. "It is a bit like coming home from work and deciding you want some food that has been at the back of the cupboard, only to find that it is past its use-by date," Kahn says of the problem. "Our device can continually monitor mechanical structures to ensure they always remains in date and will not have to be thrown out."

The team's work has been published under open-access terms in the journal IEEE Access, and patented for future commercial exploitation.