Oxidation behavior of thermally sprayed Mo-Si based composite: Effect of metastable phase, porosity and residual stress

• Published in: Journal of alloys and compounds 2019-03, Vol.776, p.712-721
• Main Authors: Sun, Jia, Fu, Qian-Gang, Li, Tao, Zhang, Guang-Peng, Yuan, Rui-Mei
• Format: Article
• Language: English
• Subjects: Composite; Composite materials; Metastable phases; Molybdenum disilicides; MoSi2; Oxidation; Oxidation resistance; Porosity; Residual stress; Silicide; Spraying; Stress concentration; Stress distribution; Thermal spray; Two dimensional composites
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.10.309

Constituent phases, porosity and residual stress are significant factors influencing the performance of two-dimension (2D) structural components. In present study, these factors with respect to thermally sprayed MoSi2 based composite were elaborately adjusted through plasma spraying power to investigate the oxidation behavior in medium temperature range of 400–900 °C. By increasing the operation powers, the improved melting degree of feedstock led to the increased metastable phases and the decreased porosity in the MoSi2 based composite but it did not remarkably affect the residual stress distribution. After the analysis on the medium-temperature oxidation, it can be concluded that the metastable phases and the porosity were principally responsible for the enhanced oxidation resistance of the MoSi2 based composite. The thermal-sprayed 2D MoSi2 based composites with large amounts of β phases and low porosity can achieve the outstanding oxidation resistance in medium temperature range. •Thermally sprayed MoSi2 based composite possessed multiphase constituents with nano/micro-scale microstructure.•Porosity of thermally sprayed MoSi2 based composite varied inversely with the amount of metastable phase.•The residual stress of varied-power sprayed MoSi2 based composites stayed same level.•Thermally sprayed composite with high amount of metastable phase and low porosity could inhibit the pulverization.