Cavitation-erosion of thermal sprayed hardfacing coatings

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6830880

Guo, X

An investigation has been carried out on the cavitation-erosion behavior of thermal sprayed WC-Co and Tribaloy (T-400) coatings. The thermal spray processes used were air and vacuum plasma spraying and hypersonic flame or Jet Kote spraying. The principal goals of this work were to investigate the influence of the three types of spray processes on the coating microstructure and cavitation-erosion behavior. It was found that spray atmosphere is a critical parameter in thermal spraying of WC-Co coatings. For the case of WC-Co materials, decomposition and dissolution of the carbide occur during air plasma and Jet Kote spraying processes, while no apparent decomposition and dissolution of the carbide were observed for vacuum plasma spraying. Tribaloy coatings produced by these three spray processes showed metastable mixtures of amorphous and microcrystalline phases, as well as supersaturated solid solution due to rapid solidification. Upon the heat treatment (at 1175 C for 5 minutes), these metastable phases were transformed to more stable phases. Laser treatment gave a dense coating surface structure, pore-free and crack-free surfaces, and resulted in significantly improved cavitation-erosion resistance. The main factors leading to enhanced cavitation-erosion resistance of the Tribaloy coatings are: (i) high coating density; (ii) high proportion of Laves phase; (iii) stress-induced phase transformation; and (iv) a low level of microstructural defects. The corrosive aspects of cavitation-erosion and electrochemical measurements showed that porosity was the predominant factor influencing cavitation-corrosion and corrosion behaviors.

• Research Organization: State Univ. of New York, Stony Brook, NY (USA)
• OSTI ID: 6830880
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360105 -- Metals & Alloys-- Corrosion & Erosion
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360205 -- Ceramics
Cermets
& Refractories-- Corrosion & Erosion
ALLOYS
AMORPHOUS STATE
CARBIDES
CARBON COMPOUNDS
CAVITATION
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COATINGS
COBALT
COBALT ALLOYS
COBALT BASE ALLOYS
CORROSION RESISTANCE
CORROSION RESISTANT ALLOYS
CRACKS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DECOMPOSITION
DENSITY
DEPOSITION
DISPERSIONS
DISSOLUTION
ELEMENTS
EMBRITTLEMENT
EROSION
HEAT TREATMENTS
IRON ALLOYS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
MIXTURES
MOLYBDENUM ALLOYS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PLASMA ARC SPRAYING
POROSITY
REFRACTORY METAL COMPOUNDS
SOLID SOLUTIONS
SOLIDIFICATION
SOLUTIONS
SPRAY COATING
SPRAYED COATINGS
SURFACE COATING
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TRIBALOY 400
TUNGSTEN CARBIDES
TUNGSTEN COMPOUNDS
WEAR RESISTANCE