03 September 2003

Early corrosion detection can save money, lives

Corrosion can affect the structural integrity and durability of metals and alloys used in pipe work, tanks, and elsewhere. Although overall metal loss may be insignificant (e.g. 5%), localized corrosion can still lead to pitting, which can lead to the cracking and eventual fractures that cause leakage or more serious failures.

Now a new technique can help detect localized corrosion in steel and other metals, which could help industry avoid major repair bills, said materials researchers at Sheffield Hallam University. In some cases, it could even help prevent serious safety problems in industrial plants and other building structures. The technique can detect corrosion on a much smaller level, which means preventative action can occur earlier, saving money, time, and possibly lives.

Historically, there has been a lack of techniques able to evaluate this type of metal loss as conventional detection methods assume that corrosion takes place uniformly.

Some scanning techniques can provide useful information on local corrosion, and this approach is growing in central Europe, the Far East, and North America. The aim of the Sheffield Hallam initiative was to develop the U.K.'s capability in this field through the use of the Scanning Vibrating Electrode Technique (SVET).

SVET involves scanning a vibrating electrode over the surface of a material immersed in the test solution, while measuring the local corrosion activity taking place at the metal-solution interface. It differs from traditional methods, because it measures this activity at a microscopic level, enabling the rate and the distribution of localized corrosion damage to undergo measurement. The use of a vibrating electrode also offers improved signal output and resolution over other "new-generation" nonvibrating probe techniques. The project team has already used the SVET system to carry out a number of interdisciplinary initiatives, many involving collaboration with industry.

"Detecting corrosion as early as possible is of vital importance to industry," said professor and team leader Bob Akid, director of the University's Center for Corrosion Technology. "By improving industry's ability to predict the onset of damage, SVET will enable effective forecasting of maintenance regimes."