Preserving cultural heritage artefacts, such as museum exhibits and historical documents, is a delicate process – the temperature and humidity of the surrounding environment must be controlled. Chemical air pollutants, which are not routinely monitored, can quickly corrode stored and displayed objects. Bronze artefacts, for example, are highly susceptible to such corrosion even in controlled museum environments.

Traditional methods to investigate corrosion involve laboratory analyses made after the fact – once the damage has been done to what are often unique and irreplaceable items. A commercial solution, a device that senses when conditions could lead to corrosion, is now on offer thanks to the EU-funded MUSECORR project.

“MUSECORR has developed a suite of user-friendly ‘AirCorr’ corrosion loggers that warn of corrosive atmospheres in real time,” explains Tomas Prosek of the Institut de la Corrosion in France. “They contain robust and highly-sensitive sensor units and can be operated by non-technical professional users. These have proved themselves in field trials, and are now seeing success in the marketplace.”

Designed to succeed

Sensitivity, miniaturisation and portability were key criteria in the project. Innovations in each of these areas, together with new software, resulted in indoor and outdoor versions of the technology, where the corrosion sensor probe itself can be switched to match the artefact material being monitored.

The technology analyses changes in electrical resistance which occurs when a metal surface is corroded by minute concentrations of chemicals in the atmosphere. The device uses replaceable thin metal films as sensor probes – just tens of nanometres thick – which are able to boost sensitivity. For outdoor sensor units, which are watertight, thicker films are used as the corrosion rate is often higher.

Field trials have demonstrated the power of the technology, as Prosek explains: “We implemented large and successful field trials among museum curators and other professionals worldwide. Of particular interest, for example, was a sensor that accompanied a unique historical tapestry lent by the Louvre to a Japanese museum. We could track the atmospheric changes during packaging and shipping, followed by display in two different galleries, one of which showed a significantly higher corrosion rate on copper parts in the tapestry.” 

On a commercial fast-track

Previously, protecting museum collections involved a great deal of faith – controlling temperature and humidity, using air filters and hoping for the best. But this approach ignores the real dangers chemical pollutants pose.

The users who took part in the field trials were delighted with the results, according to the project team. AirCorr allows users to compare and rank different display and storage environments, and make the necessary changes to prevent damage before it is too late.

“This is very new and, for sure, real-time solutions for conservation are the way to go for the future,” says Prosek.

Since the project finished mid-2012, the focus has been on commercial success. Hundreds of units were sold in 2013, and 2014 has seen growing sales boosted by word of mouth and professional testimonies, Prosek adds.

Not only is the technology generating turnover, but this same income has funded the development of new versions of AirCorr. “We are now establishing distribution channels as technical suppliers see the growing interest among a wide range of user communities,” says Prosek.

In addition to the cultural heritage sector, there has been interest shown from companies running delicate computer storage facilities, the pulp and paper industry with its highly-corrosive production environments, and even the automotive sector, which is keen to know the long-term effects of atmospheric corrosion in vehicles, he adds.

Below picture of MUSECORR device

©Fraunhofer FEP