University of Buffalo researchers have developed a graphene-based coatings that acts as an active and passive corrosion prevention barrier and can be applied using standard, off-the-shelf industrial tools. Credit: University of Buffalo; You Tube.
As ceramic engineers and scientists, it pains us to admit that there is an unwelcome member of the family—iron oxide, or rust. And like an unpleasant family member, rust is disruptive at best but more often destructive, nearly impossible to control and gets a lot of resources thrown at it to try to control it.
It’s a big problem that can be quantified in dollars and cents. A report issued last year by the National Academies Press, “Research Opportunities in Corrosion Science and Engineering,” estimates that “premature materials degradation costs industrialized nations approximately 3 percent of their gross domestic product.” In the United States that translates to losses caused by corrosion in the neighborhood of $2-4 trillion each decade. That number is so big, it is hard to grasp. According to the report, it is about equivalent to the cost of repairing the infrastructure damage wrought by Hurricane Katrina in Louisiana, Mississippi and Alabama— three or four times over!
In this context, University of Buffalo researcher, Sarbajit Banerjee and his graduate student, Robert Dennis, are making strides in this epic battle of good vs. evil with a graphene-based anti-corrosion composite coating.
In an interview, Banerjee told me that the work grew out discussions with industry to develop effective, environmentally friendly corrosion prevention coatings that could be adapted by the existing metal-finishing industry. “Working with industry keeps you on task,” he says, “so there was a big emphasis to develop a coating that could be applied with off-the-shelf equipment like brushes, sprayers, etc.”
The coating is a polyetherimide matrix with a graphene filler dispersion. The polymer is a common industrial polymer, and its role in the coating is to provide adhesion with the steel as well as to provide thermal and chemical stability. Banerjee says it has the additional advantage of blending well with graphene. At present an organic solvent is used, and the group is working on developing a water-soluble formulation.
Banerjee says the coating is effective because of it is both an active and passive coating. “It is passive in that it prevents water ions from reaching the steel,” he explains. “We also think it works as an active coating by setting up a Shottkey barrier that depletes electrons and shuts down the electrochemistry at the interface.”
The researchers are optimistic that the new coating will be an effective replacement for hexavalent chromium corrosion-prevention coatings, which have been linked to cancer-causing pollution. Banerjee hopes that many of the western New York electroplating shops will be able to retool to use a graphene-based coating.
He noted that the Brookings Institute recently provided data that the metal-finishing sector has been growing and experiencing job growth rates of about 10 percent. “Even if the steel is made somewhere else,” he says, “the finishing work must be done closer to onsite.”
“Our product can be made to work with the existing hardware of many factories that specialize in chrome electroplating, including job shops in Western New York that grew around [the former] Bethlehem Steel. This could give factories a chance to reinvent themselves in a healthy way in a regulatory environment that is growing increasingly harsh when it comes to chromium pollution” Banerjee said in a press release.
Banerjee’s work is supported by Tata Steel and the New York State Pollution Prevention Institute (a partnership among Rochester Institute of Technology, Clarkson University, Rensselaer Polytechnic Institute, University at Buffalo and the 10 NYS Regional Technology Development Centers). UB has filed an application for a provisional patent on the coatings.
The group plans to evaluate the coating’s effectiveness on other metals and against other corrosion mechanisms. “We want to find out how general of a coating it is. We will probably have to tailor it by including other components,” Banerjee says. That could include adding self-healing components, he says, which would add some “cure” with the “prevention.”