Underwater plasma spraying and synthesis of coatings
- Powder Metallurgy Inst., Minsk (Belarus)
- Drexel Univ., Philadelphia, PA (United States)
The paper presents the results of experiments relating to further development of the coating processes, based on utilizing the electric arc thermal plasma jets under water. Water is supposed to be a medium providing unique conditions for plasma behavior, that can be used for new materials processing. There are several issues under investigation: the plasma jet gas dynamics under water, the heat flow from the jet into the substrate, the processes of coatings by underwater plasma spraying and chemical vapor deposition. It is found that the local pressure in the plasma jet under water is under great influence of water column pressure. It directly reduces the plasma velocity, but increases its density. The plasma flow under water should be regarded like a channel with practically total absence of the ambient medium ejection in it. The heat flow from the jet to a plasma spot on the substrate reaches 20--30% of plasma power and concentrates in a spot with 12--17 mm diameter. This allows one to fuse the coating surface layer during spraying or to process the coatings from solid, not fused particles even in the case of refractory materials spraying. The examples are presented for underwater plasma spraying of the low oxidized coatings from metallic titanium, hard thick coatings from titanium carbide, the coatings from partially stabilized zirconia with fused surface layer as well as underwater plasma chemical vapor deposition of diamond coatings.
- OSTI ID:
- 160460
- Report Number(s):
- CONF-940684-; ISBN 0-87170-509-5; TRN: 96:006024
- Resource Relation:
- Conference: 1994 national thermal spray conference, Boston, MA (United States), 20-24 Jun 1994; Other Information: PBD: 1994; Related Information: Is Part Of 1994 Thermal spray industrial applications: Proceedings; Berndt, C.C.; Sampath, S. [eds.] [State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering]; PB: 816 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
TITANIUM
PLASMA ARC SPRAYING
TITANIUM CARBIDES
ZIRCONIUM OXIDES
YTTRIUM OXIDES
DIAMONDS
CHEMICAL VAPOR DEPOSITION
MOLYBDENUM
DESIGN
HEAT FLUX
ARGON
HYDROGEN
METHANE
OPTICAL MICROSCOPY
X-RAY DIFFRACTION
SCANNING ELECTRON MICROSCOPY
RAMAN SPECTROSCOPY
PRESSURE DEPENDENCE
MICROHARDNESS
POROSITY