Functionally graded materials (FGMs) display continuously varying compositions and/or microstructures over definable geometric orientations and distances. The grades can be continuous on a microscopic level or they can be laminates comprised of gradients of metals, ceramics, polymers or variations in porosity/density. Several processing techniques have been explored for the fabrication of FGMs for structural applications: e.g., powder metallurgy, plasma spraying, insitu synthesis, self propagating high temperature synthesis, reactive infiltration, etc. Physical and chemical vapor deposition techniques are also being explored to process FGM films with nanometer level composition gradients.
FGMs open a new dimension to high performance materials in energy, electronics and heavy machinery industries. Plasma spray processing offers a flexible and inherently economic means for producing FGMs. In fact, plasma spraying has been used for many years to apply layered and graded deposits ("bond coats") to enhance the survivability of thick ceramic Thermal Barrier Coatings (TBCs) used in heat engines. These "graded coatings" are applied to reduce discontinuities in thermal expansion coefficients in order to avoid mismatch-related failure in service.
FGM Processing
Thermal Spray Lab Home Page
SUNY Contacts:
S. Sampath
H. Herman
MIT Contacts
M. Finot
S. Suresh
03/29/02
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