Carbon/carbon(C/C)composites have been acknowledged as potential candidates in aerospace vehicles,but their oxygen sensitivity still remains an enormous challenge.In this work,a novel multilayer coating consisted of H...Carbon/carbon(C/C)composites have been acknowledged as potential candidates in aerospace vehicles,but their oxygen sensitivity still remains an enormous challenge.In this work,a novel multilayer coating consisted of HfC-2.5 mol.%Hf_(6)Ta_(2)O_(17),HfC-40 mol.%SiC,HfC-2.5 mol.%Hf_(6)Ta_(2)O_(17) and HfC-60 mol.%SiC sublayers from surface to inside was designed and fabricated on the surface of C/C composites with sharp leading edge by plasma spraying.Its ablation resistance was assessed using oxyacetylene torch with a maximum temperature over 2300℃ and compared with monolayered coatings.The multilayer coating revealed preferable ablation retardation capacity evidenced by its integrated profile and less flaw quantity.Such benefits were primarily stemmed from the effective structural design and rational material selection.The former was able to reduce the thermal stress within the ablated scale,the latter contributed to rising the high-temperature resistance and oxygen barrier ability of the coating.展开更多
A(ZrC/SiC)_(3)alternate coating was deposited on sharp leading edge(SLE)C/C composites by chemical vapor deposition(CVD).The ablation behavior was examined via oxyacetylene torch with heat flux of 2.38 MW/m^2.The resu...A(ZrC/SiC)_(3)alternate coating was deposited on sharp leading edge(SLE)C/C composites by chemical vapor deposition(CVD).The ablation behavior was examined via oxyacetylene torch with heat flux of 2.38 MW/m^2.The results indicated that the alternate coating exhibited great ablation resistance,providing an effective protection for C/C composites.In initial rapid heating stage,the(ZrC/SiC)_(3) alternate coating can relieve thermal stress,avoiding the peeling of coating and keeping an intact coating structure.In subsequent ablation,the Si C layers in central region were consumed rapidly,leaving layered interspaces.Three stacked ZrO_(2) layers were reserved with the assistance of the release of thermal stress by interspaces,offering a great anti-scouring effect.In transition and border regions,the alternate Si C layers can delay oxygen erosion of inner coating and C/C substrate by the formation of SiO_(2).It is believed that the results would be helpful for the design and application of anti-ablation coatings on SLE C/C composites.展开更多
基金supported by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University (No.CX2021006)the National Natural Science Foundation of China (Nos.91860203,51727804,and 52130205)+1 种基金the Fundamental Research Funds for the Central Universities (No.3102019TS0409)Creative Research Foundation of Science and Technology on Thermo-structural Composite Materials Laboratory.
文摘Carbon/carbon(C/C)composites have been acknowledged as potential candidates in aerospace vehicles,but their oxygen sensitivity still remains an enormous challenge.In this work,a novel multilayer coating consisted of HfC-2.5 mol.%Hf_(6)Ta_(2)O_(17),HfC-40 mol.%SiC,HfC-2.5 mol.%Hf_(6)Ta_(2)O_(17) and HfC-60 mol.%SiC sublayers from surface to inside was designed and fabricated on the surface of C/C composites with sharp leading edge by plasma spraying.Its ablation resistance was assessed using oxyacetylene torch with a maximum temperature over 2300℃ and compared with monolayered coatings.The multilayer coating revealed preferable ablation retardation capacity evidenced by its integrated profile and less flaw quantity.Such benefits were primarily stemmed from the effective structural design and rational material selection.The former was able to reduce the thermal stress within the ablated scale,the latter contributed to rising the high-temperature resistance and oxygen barrier ability of the coating.
基金the National Natural Science Foundation of China(Nos.51727804,51821091,51872233)Natural Science Basic Research Plan in Shaanxi Province of China(No.2020JQ-175)。
文摘A(ZrC/SiC)_(3)alternate coating was deposited on sharp leading edge(SLE)C/C composites by chemical vapor deposition(CVD).The ablation behavior was examined via oxyacetylene torch with heat flux of 2.38 MW/m^2.The results indicated that the alternate coating exhibited great ablation resistance,providing an effective protection for C/C composites.In initial rapid heating stage,the(ZrC/SiC)_(3) alternate coating can relieve thermal stress,avoiding the peeling of coating and keeping an intact coating structure.In subsequent ablation,the Si C layers in central region were consumed rapidly,leaving layered interspaces.Three stacked ZrO_(2) layers were reserved with the assistance of the release of thermal stress by interspaces,offering a great anti-scouring effect.In transition and border regions,the alternate Si C layers can delay oxygen erosion of inner coating and C/C substrate by the formation of SiO_(2).It is believed that the results would be helpful for the design and application of anti-ablation coatings on SLE C/C composites.
