Researchers aim to reduce corrosion in construction using new materials

(CONNECT) Corrosion and rust not only destroy buildings and infrastructure worldwide, but repairing the damage also incurs high costs and consumes significant resources. To address these issues, researchers at the Joining Technology and Corrosion Laboratory of the Swiss Federal Laboratories for Materials Testing and Research (Empa) in Dübendorf are working intensively to identify the causes and develop new materials. According to a press release, they are participating in the international project ICP Materials (International Co-operative Program on Effects on Materials, including Historic and Cultural Monuments).

The participating institutions provide data on corrosion rates to the network. Ulrik Hans from the Empa laboratory, in collaboration with the Federal Office for the Environment (FOEN), is responsible for Switzerland. To this end, so-called "released" standardized metal samples are installed at designated points. In Switzerland, they were installed on Mount Chaumont in the canton of Neuchâtel. The samples corrode there without any harmful environmental influences, due to the purely natural redox reaction between metal, water, and oxygen. Samples made of weather-resistant steel and titanium-zinc are tested here. “Titanium zinc is popular in the construction industry because it is fully recyclable. When it comes to building maintenance, it makes a significant difference whether the metal roof and gutters need to be replaced after 40 years or only after 80,” Ulrik Hans is quoted as saying in the press release.

Comparisons of data over the past 40 years show that the situation has improved. In the early 1980s, a peak level of 460 micrograms of sulfur dioxide was recorded in industrial areas (Ruhr region); currently, levels are below 10 micrograms per cubic meter. Under ideal conditions at Chaumont, the value fluctuates between 0 and 1 microgram. The figures for corrosion show a similar pattern. In 1987, 500 grams of iron oxide per square meter of steel were measured at the Kopisty site in the Czech Republic; today, the figure is between 100 and 150 grams. For zinc, the value decreased from 15 grams per square meter to 7 grams.

Researchers use the collected data to develop suitable alloys, coatings, or nanometer-thick passive layers that curb corrosion. State-of-the-art surface analysis techniques, such as Kelvin probe force microscopy and X-ray photoelectron spectroscopy (HAXPES), are used here.

In addition to materials science, the ICP Materials network monitors 26 UNESCO World Heritage sites.

Participants in the project include researchers from the RISE Research Institute in Gothenburg, Sweden; the German Federal Institute for Materials Research and Testing in Berlin; the University of Žilina (Silein) in Slovakia; the Warsaw University of Technology; and the Italian agency ENEA. A recent study has been published in the journal “Corrosion and Materials Degradation.” ce/ww