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| Abstract No.: |
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| Title: |
Powder particle size effect on the reaction and oxidation behavior during plasma spraying of Ni-Al composite powders
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| Authors: |
Chang-Jiu Li / Xi'an Jiaotong University, P.R. China
Li Zhang* / Xi'an Jiaotong University, P.R. China
Shan-Lin Zhang/ Xi'an Jiaotong University, China
Xiao-Tao Luo/ Xi'an Jiaotong University, China
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| Abstract: |
It was known for long that Ni-Al composite powder can be used to deposit self-bonding coating and thus bond coat for common ceramic coatings, supposing to be contributed by exothermic reaction. However, it was found that with commercial Ni-Al composite powders with a large particle size it is difficult to ignite the self-propagating reactions between Ni and Al and form NiAl intermetallic coatings by plasma spraying. In this study, the nickel-aluminum composite powder particles of different sizes were used to prepare NiAl intermetallics-based coatings by plasma spraying. The dependences of exothermic reaction of Ni and Al elements and droplet oxidation behavior during in-flight on powder particle size and spray parameters were investigated. Scanning electron microscope (SEM) was employed to characterize the interface bonding within the coatings and between the coatings and the substrate. Energy dispersive spectroscopy (EDS) was used to analyze the element distributions in the coatings deposited at different spray distances to examine the reation kinetics during particle in-flight. The mechanical properties of prepared coatings were evaluated by tensile tests. The results show that particle size of nickel-aluminum composite powders is a dominant factor determining the formation of NiAl through exothermic reaction during plasma spraying.
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