研究目的
To study and compare the effect of TiC on the microstructure and irradiation characteristics of tungsten-based coatings fabricated by supersonic atmospheric plasma spraying (SAPS) technique.
研究成果
The TiC-doped coating exhibited superior properties including denser structure, lower porosity, reduced oxygen content, higher thermal conductivity, and better resistance to laser irradiation compared to the TiC-free coating. TiC addition refined tungsten grains and hindered crack formation, enhancing irradiation stability. The findings suggest that TiC-doped tungsten-based coatings prepared by SAPS are promising for plasma-facing components in nuclear fusion devices, with recommendations for further optimization and testing under varied conditions.
研究不足
The study was conducted under specific laser irradiation conditions (e.g., power, spot size) which may not represent all irradiation scenarios. Oxidation during SAPS and potential gas introduction could affect results. The use of TiC with lower melting point than tungsten might have limitations in high-temperature applications. The research is limited to laboratory-scale experiments and may not fully replicate fusion device environments.
1：Experimental Design and Method Selection:
The study involved fabricating TiC-free and TiC-doped tungsten-based coatings using SAPS, followed by laser irradiation to simulate irradiation conditions. The rationale was to investigate how TiC addition affects coating properties under irradiation. Theoretical models include phase analysis and thermal conductivity measurements.
2：Sample Selection and Data Sources:
Commercially available pure tungsten powders (purity > 99.9%, size 10–20 μm) and tungsten-based composite powders with 1.5 wt% TiC (purity > 99.9%, size 2–10 μm) were used. Coatings were sprayed on reduced activation steel substrates.
3：9%, size 10–20 μm) and tungsten-based composite powders with 5 wt% TiC (purity > 9%, size 2–10 μm) were used. Coatings were sprayed on reduced activation steel substrates.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: SAPS system (HEPJet-II, China), transverse flow CO2 laser (DJ-HL-T5000B, China), optical microscope (OM, Leica DM4000M, Germany), scanning electron microscope (SEM, JSM-6490 and SU-8020, Japan), energy dispersive X-ray spectrometer (EDS, Oxford, Japan), X-ray Photoelectron Spectrometer (XPS, Escalab250Xi, Thermo Scientific, USA), X-ray diffractometer (XRD, D/MAX-2500V, Japan). Gases: argon and hydrogen for plasma formation and carrier.
4：Experimental Procedures and Operational Workflow:
Powders were sprayed using SAPS with specified parameters (power 60 kW, primary gas 120 L/min argon, second gas 22 L/min hydrogen, carrier gas 8 L/min argon, spray distance 110 mm, traverse speed 300 mm/s, powder feed rate 20 g/min). Coatings were irradiated with laser (power 2.50 kW, spot diameter 2 mm, traverse velocity 300 mm/min) under argon protection. Microstructure and phase analysis were conducted using OM, SEM, EDS, XPS, and XRD.
5：50 kW, spot diameter 2 mm, traverse velocity 300 mm/min) under argon protection. Microstructure and phase analysis were conducted using OM, SEM, EDS, XPS, and XRD.
Data Analysis Methods:
5. Data Analysis Methods: EDS for element distribution, XPS for phase verification, XRD with Rietveld refinement (RIETAN-FP software) for phase composition analysis. Density, porosity, oxygen content, specific heat capacity, thermal diffusivity, and thermal conductivity were measured as per previous work.
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