Applying Perfect Coatings

To say that directed vapor deposition is a bit like spray painting barely hints at the power of this revolutionary new technology. It coats materials with a higher degree of control and efficiency than any other process. It can be used to apply coatings composed of exotic molecules and to produce layers that are not only extremely fine but also have novel properties because of the way the molecules are placed on the surface. Equally impressive, the vapor can be directed exclusively at the target and not the surrounding area, even coating surfaces that are outside the line of sight.

For more than a decade, research teams led by Haydn Wadley, University Professor and the Edgar Starke Research Professor of Materials Science and Engineering, have been world leaders in developing techniques that greatly expand the potential of this technology. Among other projects, Wadley has created coatings that protect materials from heat and produced thin films for lithium ion battery systems.

In directed vapor deposition, materials are vaporized using electron-beam guns similar to those used to create semiconductors a microscopic layer at a time. These guns, however, have been specially modified to permit their operation in a low vacuum environment, making it possible to envelop the evaporated materials in a jet of carrier gas. By manipulating this gas, operators can control the evaporants with unequaled precision. “We set up the specific conditions required for the assembly of molecules on a surface,” Wadley explains. “We can control the direction from which they arrive, their energy and motion on the surface, and other conditions that determine their properties.”

Wadley sees himself engaged in the interrelated activities of training students and doing basic research at the frontiers of materials science and physics. While his focus is on fundamental research, there are occasions when his work has led to patentable discoveries. Wadley believes that having U.Va. intellectual property available to be licensed by start-up companies is an important way to further economic development. He cites Stanford University as an academic institution that has had a profound impact on the economy in the surrounding region, and he stresses that the decline in industrial research and development makes the role of universities even more critical.

In 2000, Directed Vapor Technologies International (DVTI) was formed to capitalize on Wadley’s patents associated with creating and controlling the assembly of materials from vapor. “As it turns out, directed vapor deposition is an economical way to coat materials and make thin films,” Wadley says.

“AT DVTI, our job is to take basic research and explore its application for a variety of purposes,” says Harry Burns, CEO and president of DVTI. “When you have a technology that is as powerful and flexible as directed vapor deposition, that’s a big job.” DVTI is working with government and industry partners to develop coatings that protect surfaces from heat, wear, and corrosion. When used in airplane engines, for instance, DVTI’s thermal barrier coatings can reduce fuel consumption or increase engine thrust. DVTI is also working on coatings that could pave the way to longer superconductive cables and to improve the efficiency of solid oxide fuel cells and batteries.

Currently, DVTI is working with its partners to optimize the technology and developing prototypes for specific applications, a process that entails conducting extensive testing. “Testing is particularly important with conservative industries like aircraft manufacturing that are extremely careful about adopting new technologies,” Burns notes. As part of this effort, DVTI has built a production-scale coating machine at its Charlottesville facility.

At the same time, Wadley follows the development of the company with interest. “The work done at DVTI sometimes points to areas where there is a lack of fundamental knowledge,” he says. “It serves to help us see our research in a different context and suggests directions for future inquiries.”