Thermal Plasma Coating Technologies
The emphasis in this Thrust Area is on establishing and broadening the
science and technology bases for high rate, economical coating processes,
including plasma spraying, wire arc spraying and thermal plasma chemical
vapor deposition (TPCVD). A combination of advanced diagnostics and
modeling is used to enhance our understanding of the fundamentals of the
interactions between plasmas and particles or liquid droplets and chemical
precursors for the coatings. This understanding then provides the
guidelines for developing new equipment and process designs, such as
nozzles and shrouds to modify the fluid dynamics, and for developing
sensors and control strategies for advanced process controls. These
activities will lead to improved process tolerance against the influences
of uncontrolled parameters.
Specific activities which are presently being pursued are:
A) Plasma spraying:
* Nozzle and shroud development and evaluation for increased plasma jet
stability, and improved deposition efficiency and consistency of coating
* Development of sensors and control algorithms for detecting and avoiding
variations in plasma jet behavior and coating quality.
B) Wire arc spraying:
* Spray pattern control through different nozzle and shroud designs.
* Development of fundamental process correlations using process models and
advanced diagnostics with a novel torch.
* Application of novel control algorithm based on computer analysis of arc
C) Thermal plasma CVD:
* Texture control during high rate diamond film deposition through
detailed understanding of the boundary layer chemistry based on modeling
and diagnostics using gas chromatography.
* Arcjet deposition at high rates of hard, boron containing films.
There are several complementary projects spanning a wide spectrum from
fundamental studies in arc technologies, electrode attachment control and
plasma heat transfer to specific industrial applications.
Recent collaborations with industrial partners:
* Plasma spray model for process control development.
* High definition arc spray system development.
* Torch cathode erosion mechanism investigation.
* Barrier discharge characterization.
Collaborations with other laboratories:
Stanford University High Temperature Gas Dynamics Laboratory; SUNY Stony
Brook Thermal Spray Laboratory, University of Limoges, France: Technical
University of Ilmenau, Germany; University of Tokyo, Japan; University of
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