Abstract No.:
2763

 Title:
Suppressing oxidation of NiCr alloy with addition of Si, B, and C in atmospheric plasma spray process

 Authors:
Zhensu Zeng / Kurashiki Boring Co. Ltd., Japan
Nobuaki Sakoda/ Kurashiki Boring Kiko Co. Ltd., Japan
Sayaka Tajiri/ Kurashiki Boring Kiko Co. Ltd., Japan
Seiji Kuroda/ National Institute for Materials Science, Japan
Masayuki Komatsu/ National Institute for Materials Science, Japan

 Abstract:
Oxidation is a serious issue for thermally sprayed alloy coatings, especially in atmospheric plasma spray (APS) process, by which it is believed to be impossible to obtain alloy coatings with low oxide content. Oxidation behavior of Ni20Cr alloy and NiCrSiBC alloy in APS were compared by evaluating collected in-flight particles and sprayed coatings in our previous study. The results clearly show that the oxide content in the in-flight particles and coating of NiCrSiBC alloy was significantly lower than that of Ni20Cr alloy. In the present study, effects of particle temperature and velocity on the oxidation of the NiCrSiBC alloy were investigated. It was found that increasing particle temperature and velocity did not affect the oxidation of in-flight particle in the NiCrSiBC alloy but significantly increased the oxidation after particle impacting substrate. The results are discussed in conjunction with effectiveness of preferential oxidation of Si, B, C and simultaneous vaporization of the formed oxides on suppressing in-flight oxidation and influence of a large amount of sub-particles produced upon impacting substrate on oxidation characteristics when increasing particle temperature and velocity.

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