Innovators at NASA's Glenn Research Center have adapted a process to apply thermal and environmental barrier coatings using a unique combination of a plasma spray (PS) process and a physical vapor deposition (PVD) process to improve the coverage and quality of the coatings. Built-up layers that are smooth, thin, strain-tolerant, heat-resistant, and steam-resistant can be generated with this multi-layer system architecture in a one-step coating process.
NASA Glenn's scientists are using the combined PS-PVD process to create layers of thermal and environmental barrier coatings that may be deposited from a liquid phase, a vapor phase, or both liquid and vapor phases simultaneously. This technology allows layers to be generated with a multi-system architecture, forming both planar and columnar structures, in a faster one-step coating process.
The high-velocity, plasma-enhanced, vapor phase deposition of the coating material provides non-line-of-sight surface coatings that enable coating of complex shapes. Standard methods, such as atmospheric plasma spray and electron beam/physical vapor deposition, only have line-of-sight capability, which is limited to simple shapes. With this approach, many layers can be applied, each with an application-specific micro-structure; for example, the PS-PVD method creates a barrier coating layer, an intermediary layer, and a topcoat layer that together help optimize performance of components in extreme environments.