Leo and Cold Spray have something in common—fortunate accidents. Leo was originally a mechanical engineer who spent time in a materials science lab in Brazil. Cold Spray was a test gone wrong (or right) at a Russian University. Luckily, these serendipitous events enabled cold spray and a talented engineer to come together in the Global Research labs in upstate New York to develop a technology that will repair and even build up parts like never before.
We sat down with Leo to ask him about the technology and learn a bit about the guy behind the spray gun. Meet Leo.
Describe this technology in three sentences. Ready, Set, Go.
We propel metal powders at a very high speed using high pressure gases, and spray them onto a substrate. The impact velocities are in the order of one kilometer a second. The kinetic energy stored in the particles is sufficient to deform and locally heat the surface of the powder particles to a point that they weld to the substrate.
What’s the history of cold spray and where did the technology come from?
Cold Spray was invented in Russia in the mid-80s—by accident. Scientists were trying to put copper particles in a wind tunnel to study two-phase supersonic flows. Because those particles were flying so fast, they started depositing on the surface of the part, instead of going around it. It was this fortunate accident that they realized they can potentially use this technique to make a coating. So they started designing nozzles to form coatings. And the rest, was history.
How is cold spray used today?
Today, cold spray is mostly used for repair. The biggest application in the US is for the US army to repair helicopter parts that are made out of magnesium alloys. When the parts are corroded, they need to be replaced and there is not a good way to repair these parts. You can’t weld magnesium, so cold spray is used to build up the original geometry of the part after grinding away the corroded material. Cold spray is also used for heat sinks in the electronic industry, corrosion protection for the oil and gas industry, restoration of Al propellers on military cargo planes, repair of landing gears for helicopters and more.
What is GE doing that’s so different and unique with cold spray?
Most of the work that’s being done today, at least commercial, is soft, low temperature alloys, like copper, aluminum and zinc. The challenge was to use this technology to produce high quality deposits made of high temperature Ni and Ti alloys. We are developing better and commercially viable cold spray processes for materials of interest to GE. The other key difference of the work done at GE Global Research is the development of cold spray for additive manufacturing, where we adapt this novel coating process to build 3D shapes.
In the future, what kind of parts can you imagine cold spray building?
Aircraft engine parts like vanes, casings, bosses and fan blades. The niche for 3D parts is where the size limit for current powder-bed laser additive processes has been reached.
What is most exciting to you about this project?
I worked on cold spray in the early days when the technology was not commercially available before joining GE. Then, I was at the right place and the right time when we were getting into this technology and it was always something I had fun doing. It was my pet project!
What types of expertise were involved in this project from GE Global Research and how has this combined expertise impacted the project?
We need experts in materials science, mechanical engineering, fluid dynamics, and thermal spray. I have always worked with very diverse groups, but the uniqueness here at Global Research is that we have all of these resources in one place, simplifying the path to advance the technology in a very short time.
Why did you decide to become a Materials Engineer?
It was an accident. My background is in mechanical engineering. and I was an intern in a lab in the materials science department at UFRJ in Rio-Brazil. The job market was in bad shape when I finished my undergrad, so I continued my studies in the area just because I was familiar with it and people were happy with my work. The more I learned about the technology, the more I was attracted to it.
What do you like to do outside of the labs?
Outside the lab, I like hiking and kayaking. That’s usually what I do in my free time!
Interested in learning more? Check out the news release and other coverage on this story appearing on Ideas Lab and GE Reports. We are looking for a Coatings Materials Scientist to join our lab. If you’re interested, view the job description here.