Different oxidation protection mechanisms of HAPC silicide coating on niobium alloy over a large temperature range
| Autor: | Guang-Peng Zhang, Tao Li, Qiangang Fu, Jia Sun |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Volatilisation Niobium alloy Mechanical Engineering Metallurgy Metals and Alloys Halide 02 engineering and technology engineering.material Atmospheric temperature range 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound Coating chemistry Mechanics of Materials Cementation (metallurgy) Silicide Materials Chemistry engineering 0210 nano-technology Eutectic system |
| Zdroj: | Journal of Alloys and Compounds. 790:1014-1022 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2019.03.229 |
| Popis: | Oxidation behaviors of halide activated pack cementation (HAPC) silicide coatings on niobium alloy were elaborately studied by experimental and theoretical analysis. The HAPC process was performed with a commonly applied powder pack of Si, NH4F, and Al2O3 filler. Adsorptive Al2O3 particles from the pack from HAPC process played a positive role against oxidation at 700 °C (the so-called pest temperature). Above this temperature, the passion behavior rather than pulverization gradually appeared by the occurrence of seal-healing SiO2. However, the seal-healing effect was meanwhile weakened by the generation of the volatilized Si-O (g) species when the temperature rose up to the eutectic point of Nb2O5-SiO2 system. Continuously temperature-elevated (1500–1700 °C) oxidation overwhelmingly destroyed the surface protective scale by the depletion of melting Nb2O5 and the volatilization of SiO2 (g), leading to a catastrophic failure of structural integrity for the coated samples. |
| Databáze: | OpenAIRE |
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