New coating protects steel and superalloys

Mar 23, 2006
New coating protects steel and superalloys
An electron micrograph of a coated 316 stainless steel coupon in cross-section shows the diffusion-reaction layers. Starting from the left hand side of the photo, which is the surface of the steel the following layers are visible: 1) Aluminum oxide outer layer (not visible at lower magnifications) 2) FeAl layer, 3) Fe3Al inner layer, and 4) 316SS.

Researchers at Pacific Northwest National Laboratory have developed a new ceramic-based coating for steel and superalloys that prevents corrosion, oxidation, carburization and sulfidation that commonly occur in gas, liquid, steam and other hostile environments.

The low-cost, easy-to-apply material is available for licensing and joint research opportunities through Battelle, which operates PNNL for the Department of Energy and facilitates the transfer of lab-created technologies to the marketplace.

The new coating bonds with the metal substrate and is “resilient, inexpensive and simple,” said PNNL scientist Chuck Henager. Because the coating is fabricated at significantly lower temperatures than typically required for conventional ceramic coatings, the new process also can save energy and reduce harmful emissions, he said.

Researchers created the coating by mixing a liquid preceramic polymer with aluminum metal-flake powders to form a slurry that can be applied to a metal object by dipping, painting or air-spraying. A low-temperature curing process follows, using a commercial Ruthenium-based catalyst that enables polymer cross-linking and dries the slurry to a green state.

The coated steel is then heated in air, nitrogen or argon at 700 to 900 degrees Celsius. The heat converts the green state layer into an aluminum diffusion/reaction layer that permeates surface of the steel and provides an aluminide surface coating on the steel.

According to PNNL Commercialization Manager Eric Lund, the diffusion reaction makes the coating so durable that it can’t be chipped or scratched off.

The reaction layer on the surface of the steel is much stronger than an external coating because it is an integral part of the steel, Henager said. This layer develops during use as the coating is heated at very high temperatures, such as those that occur with the heating of pipes in a process facility.

Unlike similar products, the liquid form of the coating can be applied with a spray gun. This feature makes the PNNL coating practical for protecting large areas, researchers said.

Source: PNNL

Explore further: UCI team is first to capture motion of single molecule in real time

add to favorites email to friend print save as pdf

Related Stories

Tandem microwave destroys hazmat, disinfects

4 minutes ago

Dangerous materials can be destroyed, bacteria spores can be disinfected, and information can be collected that reveals the country of origin of radiological isotopes - all of this due to a commercial microwave ...

Earthworms as nature's free fertilizer

14 minutes ago

Earthworm presence in the soil increases crop yield, shows a new study that was published this week in Scientific Reports. "This is not unexpected," says Jan Willem van Groenigen, associate professor in the ...

Recommended for you

And so they beat on, flagella against the cantilever

4 hours ago

A team of researchers at Boston University and Stanford University School of Medicine has developed a new model to study the motion patterns of bacteria in real time and to determine how these motions relate ...

Tandem microwave destroys hazmat, disinfects

8 hours ago

Dangerous materials can be destroyed, bacteria spores can be disinfected, and information can be collected that reveals the country of origin of radiological isotopes - all of this due to a commercial microwave ...

Physicists design zero-friction quantum engine

8 hours ago

(Phys.org) —In real physical processes, some energy is always lost any time work is produced. The lost energy almost always occurs due to friction, especially in processes that involve mechanical motion. ...

Cornell theorists continue the search for supersymmetry

10 hours ago

(Phys.org) —It was a breakthrough with profound implications for the world as we know it: the Higgs boson, the elementary particle that gives all other particles their mass, discovered at the Large Hadron ...

User comments : 0