Breakthrough in corrosion prediction

Heavily corroded thallium metal rod. Length ca. 5cm. Image courtesy of Dschwen via Wikimedia Commons
Heavily corroded thallium metal rod. Length ca. 5cm. Image courtesy of Dschwen via Wikimedia Commons

New research could lead to a significant reduction in corrosion, an issue that has long been a costly one for a range of fluid handling applications.

Researchers at Oregon State University and the University of California, Berkley, have developed what they claim is a new, better approach to predict how metals react with water. Their new computational method combines two techniques, allowing predictions to be made faster, cheaper and more effectively.

The vast majority of metals react with water, the only exception being expensive precious metals like gold and silver. "We'd like to predict the specific reactions of metals and combinations of metals with water and what the products of those reactions are, by computational methods first as opposed to determining them experimentally," said Doug Keszler, professor of chemistry and director of the Center for Sustainable Materials Chemistry at OSU.

Traditionally, it is assumed that when metal is dissolved in water it forms a simple salt, but that’s not always the case. "In many cases, it initially dissolves to form a complex cluster that contains many metal atoms," explained Keszler. "We can now predict the types of clusters that exist in solution, therefore furthering the understanding of metal dissolution from a computational point of view."

The team’s research has led them to arrive at a quantitative evaluation of cluster stability as a function of pH and concentration. With clusters playing a pivotal role in chemical processes ranging from biomineralisation to solution deposition of thin films for electronics applications, understanding them is pivotal. In addition, characterising corrosion stems from being able to depict metals' stable phases in water.

"If you're designing a new steel for a bridge, for example, you'd like to include the potential for corrosion in a computational design process," Keszler said. "Or if you have a new metal for an aircraft engine, you'd like to be able to determine if it's going to corrode."

The findings have the potential to transform the way predictions are made about how metals will react with water, something which could have benefits for anything from engine manufacturing to plant design and the development of fluid handling equipment such as pumps, pipes, valves and sensors.

"Most Pourbaix diagrams do not include these metal clusters and hence our understanding of metal dissolution and reaction with water has been lacking," said study co-author Kristin A. Persson, professor of materials science at UC Berkeley. "We have now uncovered a fast and accurate formalism for simulating these clusters in the computer, which will transform our abilities to predict how metals react in water."

The teams findings have been published in the journal Nature Communications

Heavily corroded thallium metal rod. Length ca. 5cm. Image courtesy of Dschwen via Wikimedia Commons