Oxidation and ablation protection of double layer HfB2-SiC-Si/SiC-Si coating for graphite materials
| Autor: | Tian-Yu Liu, Xinyan Yue, Hongqiang Ru, Cuiping Zhang, Yan Jiang, Wei Wang |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Scanning electron microscope Mechanical Engineering Metals and Alloys Oxide 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Exfoliation joint 0104 chemical sciences Thermal barrier coating chemistry.chemical_compound Coating chemistry Mechanics of Materials Materials Chemistry engineering Graphite Composite material 0210 nano-technology Layer (electronics) |
| Zdroj: | Journal of Alloys and Compounds. 782:761-771 |
| ISSN: | 0925-8388 |
| Popis: | In order to protect graphite from oxidation and ablation, novel double layer HfB2-SiC-Si/SiC-Si coatings were designed and fabricated by a joint process of slurry method and gaseous silicon infiltration on graphite substrates. X-ray diffraction analysis and scanning electron microscopy were used to study the phase composition and microstructure of the as-fabricated coatings. The tests of oxidation and oxyacetylene flame were conducted to assess the oxidation and ablation resistance ability of the HfB2-SiC-Si/SiC-Si coatings. Results indicated that the coated samples can endure 752 h and 1200 h of oxidation at 900 °C and 1500 °C with weight gains of 0.099% and 0.26%, respectively, whereas the coated sample had a weight gain of 0.34% after 230 h of oxidation at 1600 °C. The compact double layer structure of coating resulted in the attractive anti-oxidation property at low temperature (900 °C), while the good oxidation and exfoliation resistance at high temperatures (1500–1600 °C) were ascribed to the formed compound silicate oxide layer comprising SiO2 and HfSiO4 on the coating surface. Meanwhile, the fabricated coating exhibited good ablation resistance property, after ablation for 90 s with a heat flux of 2.38 MW/m2, the mass and linear ablation rates of the coated sample were 0.36 mg/s and −0.31 μm/s, respectively. The formed compound oxides containing HfO2 and SiO2 on the surface acted as a thermal barrier that prevented the further consumption of coated sample. |
| Databáze: | OpenAIRE |
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