Durability + Design
Follow us on Twitter Follow us on LinkedIn Like us on Facebook Follow us on Instagram Visit the TPC Store
Search the site

 

D+D News

Main News Page


Team Develops Coating for Steel

Monday, November 2, 2015

More items for Coatings Technology

Comment | More

Harvard researchers say they have developed a coating that makes steel stronger, safer and more durable.

Made from rough nanoporous tungsten oxide, the coating is described as the “most durable anti-fouling and anti-corrosive material to date, capable of repelling any kind of liquid even after sustaining intense structural abuse,” according to the team from Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).

framed building
©iStock.com / WichitS

The development has a wide range of potential applications, including medical devices and buildings.

The new material has a broad range of potential applications, including non-fouling medical tools and devices, such as implants and scalpels, nozzles for 3D printing and, potentially, larger-scale applications for buildings and marine vessels, the university reported in an Oct. 20 research announcement.

From the SLIPS Lab

The technology is the latest in a series of other non-stick, anti-fouling materials developed in the lab of Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science and core faculty member of the Wyss Institute for Biologically Inspired Engineering at Harvard University.

Aizenberg’s team developed Slippery Liquid-Infused Porous Surfaces in 2011 and since then has demonstrated a broad range of applications for the super-slick coating, known as SLIPS.

The new SLIPS-enhanced steel is described in Nature Communications.

“Our slippery steel is orders of magnitude more durable than any anti-fouling material that has been developed before,” Aizenberg said in a statement.  “So far, these two concepts—mechanical durability and anti-fouling—were at odds with each other. We need surfaces to be textured and porous to impart fouling resistance but rough nanostructured coatings are intrinsically weaker than their bulk analogs. This research shows that careful surface engineering allows the design of a material capable of performing multiple, even conflicting, functions, without performance degradation.”

How it Works

The biggest challenge in the development of this surface was to figure out how to structure steel to ensure its anti-fouling capability without mechanical degradation.

Thus, the team used an electrochemical technique to grow an ultrathin film of hundreds of thousands of small and rough tungsten-oxide islands directly onto a steel surface.

“If one part of an island is destroyed, the damage doesn’t propagate to other parts of the surface because of the lack of interconnectivity between neighboring islands,” explained  Alexander B. Tesler, former postdoctoral fellow at SEAS, current research fellow at Weizmann Institute of Science in Israel and the paper’s first author.

“This island-like morphology combined with the inherent durability and roughness of the tungsten oxide allows the surface to keep its repellent properties in highly abrasive applications, which was impossible until now.”

Electrochemical deposition is already a widely used technique in steel manufacturing, according to Aizenberg.

“I don’t want to create another line that would cost millions and millions of dollars and that no one would adopt,” Aizenberg said.

The goal is to be scalable, but not disruptive to current industry practices, she added.

Testing the Coating

To test the material, the team scratched it with stainless steel tweezers, screwdrivers, diamond-tipped scribers, and pummeling it with hundreds of thousands of hard, heavy beads.

Then, the team tested its anti-wetting properties with a wide variety of liquids, including water, oil, highly corrosive media, biological fluids containing bacteria and blood.

testing
Harvard University

The team performed accelerated corrosion tests, in which unmodified stainless steel (300 grade) (right sample) and the lower part of the tungsten oxide-SLIPS sample with a 600-nm-thick porous tungsten oxide film on steel (left sample) were exposed to very corrosive Glyceregia stainless steel etchant. The images show corrosion evolution as a function of contact time.

Not only did the material repel all the liquid and show anti-biofouling behavior, but the tungsten oxide actually made the steel stronger than steel without the coating, the team reported.

“This research is an example of hard core, classic material science,” said Aizenberg. “We took a material that changed the world and asked, how can we make it better?”

   

Tagged categories: Architecture; Coatings Technology; Engineers; Marine Coatings; Research and development; Steel; Structural steel

Comment Join the Conversation:

Sign in to our community to add your comments.

Advertisements
 
Shield Industries, Inc
 
FireGuard® E-84 Intumescent Coating - Shield Industries, Inc
 
Trust the certified protection of the industry’s most innovative intumescent coating FireGuard® E-84 to provide you with the 1 and 2 hour fire ratings you need.
 

 
Novatek Corporation
 
Novatek Portable Air Filtration Systems
 
Air Scrubbers/Negative Air machines for restoration, abatement, dust & odor control, hazardous contaminant removal from job sites to clean rooms and hospitals. Portable, affordable!
 

 
Keim Mineral Coatings
 
Mineral Silicate Paints + Stains Fuse to Concrete
 
• Forms permanent chemical bonds
• Becomes part of the concrete
• Will never peel
• Looks completely natural
 

 
 
 

Technology Publishing Co., 1501 Reedsdale Street, Suite 2008, Pittsburgh, PA 15233

TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL webmaster@durabilityanddesign.com


The Technology Publishing Network

Durability + Design PaintSquare the Journal of Protective Coatings & Linings Paint BidTracker

 

© Copyright 2012-2018, Technology Publishing Co., All rights reserved