Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5465607 | Surface and Coatings Technology | 2017 | 40 Pages |
Abstract
La-doped Mo-Si (LMS) ceramic coatings were deposited on SiC-coated carbon/carbon (C/C) composites using plasma spraying at different spraying powers. The effect of spraying power on the microstructures and properties of LMS coatings was investigated. The feedstock particles were sufficiently melted and LMS coatings became more and more compact with the increase of spraying power. Especially at the power of 55Â kW, a denser layer of LMS coating was obtained, which has a remarkable oxidation resistance with a mass loss of only 1.18% by comparing with other powers after oxidation in air at 1773Â K for 100Â h. The achieved LMS coating could endure thermal shock between 1773Â K and room temperature for 25 times. Meanwhile, the final mass loss rate (0.02476) was several times lower than that of other spraying powers after the thermal cycling test. Compared with the power of 45Â kW, the adhesive strength and micro-hardness of sprayed LMS coating in 55Â kW were increased by 33.4% and 39.3%, respectively, which are primarily ascribed to the integrity of the oxidized coating with continuous SiO2-rich La-Si-O glass film and silicate protective scale under the appropriate power. However, the defects of surface cracks, penetrating cracks and needle-like particles were produced within the coating when the spraying power was 60Â kW due to the excessive power.
Keywords
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Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Changcong Wang, Kezhi Li, Xiaohong Shi, Caixia Huo, Qinchuan He, Yudan Zhang,