With the TiB2−SiC powders after spray granulation and vacuum calcination as raw materials,the TiB2−SiC coating was prepared by supersonic atmospheric plasma spraying(SAPS).The effects of spraying power and spraying di...With the TiB2−SiC powders after spray granulation and vacuum calcination as raw materials,the TiB2−SiC coating was prepared by supersonic atmospheric plasma spraying(SAPS).The effects of spraying power and spraying distance on the properties of the TiB2−SiC coating were investigated and the fabrication processing of SAPS was optimized.The results show that the sprayed powders after calcination have a uniform particle size distribution,good sphericity and enhanced fluidity.The coating prepared by the calcined powders has a dense structure and high deposition efficiency.When the calcined TiB2−SiC powders are used and the spraying power is 95 kW and the spraying distance is 150 mm during supersonic plasma spraying,the obtained TiB2−SiC coating behaves the best comprehensive performance with the porosity,microhardness,bonding strength and resistivity equal to 5.6%,3.57 GPa,18.3 MPa and 10.8 mΩ·cm,respectively.展开更多
To prevent the C/C composites from ablation, HfC-HfO2 protective coating was prepared by supersonic atmospheric plasma spraying. The morphology and microstructure of HfC-HfO2 coating were characterized by X-ray diffra...To prevent the C/C composites from ablation, HfC-HfO2 protective coating was prepared by supersonic atmospheric plasma spraying. The morphology and microstructure of HfC-HfO2 coating were characterized by X-ray diffraction and scanning electron microscopy. The ablation resistance test was carried out by an oxyacetylene torch. The results show that the as-prepared coating is dense with little pinholes and crack free. The elements Hf, C and O were uniformly distributed in the cross-section. After ablation for different time, the mass ablation rate fluctuated along with the change of ablation time. The ablation process of the surface coating could be divided into rapid oxidation and solid state sintering stages. During ablation, an Hf CxOy-HfO2 transitional layer was generated in the coating, which resulted from the active oxidation of Hf C. After cooling, some microcracks were observed on the surface of coating, and the structure of cross-section was broken, which were due to the phase transition of HfO2.展开更多
基金The authors are grateful for the financial supports from Guangdong Academy of Sciences Project(2018GDASCX-0402)of China,Yunnan Science and Technology Plan Project of China(2018IC080)the Natural Science Foundation of Hunan Province of China(2018JJ2524).
文摘With the TiB2−SiC powders after spray granulation and vacuum calcination as raw materials,the TiB2−SiC coating was prepared by supersonic atmospheric plasma spraying(SAPS).The effects of spraying power and spraying distance on the properties of the TiB2−SiC coating were investigated and the fabrication processing of SAPS was optimized.The results show that the sprayed powders after calcination have a uniform particle size distribution,good sphericity and enhanced fluidity.The coating prepared by the calcined powders has a dense structure and high deposition efficiency.When the calcined TiB2−SiC powders are used and the spraying power is 95 kW and the spraying distance is 150 mm during supersonic plasma spraying,the obtained TiB2−SiC coating behaves the best comprehensive performance with the porosity,microhardness,bonding strength and resistivity equal to 5.6%,3.57 GPa,18.3 MPa and 10.8 mΩ·cm,respectively.
基金supported by the National Natural Science Foundation of China under Grant Nos. U1435202 and 51521061the “111” Project under Grant No. 08040the Research Fund of the State Key Laboratory of Solidification Processing (Northwestern Polytechnical University), China (Grant No. 142-TZ-2016)
文摘To prevent the C/C composites from ablation, HfC-HfO2 protective coating was prepared by supersonic atmospheric plasma spraying. The morphology and microstructure of HfC-HfO2 coating were characterized by X-ray diffraction and scanning electron microscopy. The ablation resistance test was carried out by an oxyacetylene torch. The results show that the as-prepared coating is dense with little pinholes and crack free. The elements Hf, C and O were uniformly distributed in the cross-section. After ablation for different time, the mass ablation rate fluctuated along with the change of ablation time. The ablation process of the surface coating could be divided into rapid oxidation and solid state sintering stages. During ablation, an Hf CxOy-HfO2 transitional layer was generated in the coating, which resulted from the active oxidation of Hf C. After cooling, some microcracks were observed on the surface of coating, and the structure of cross-section was broken, which were due to the phase transition of HfO2.
