In order to effectively employ the unique high temperature mechanical properties of carbon/carbon composite substrates, SiC coatings reinforced by SiC whiskers were prepared by pack cementation method. The effect of S...In order to effectively employ the unique high temperature mechanical properties of carbon/carbon composite substrates, SiC coatings reinforced by SiC whiskers were prepared by pack cementation method. The effect of SiC whiskers on the oxidation resistance properties of the single-layer coating and double-layer coating was investigated. SiC whiskers in the single-layer SiC coating have little effect on the anti-oxidation property but obviously improve the thermal shock property. The double-layer coating with inner-layer reinforced coating exhibits more perfect anti-oxidation ability than the double-layer coating with SiC inner-layer coating.展开更多
To meet the increasing demand for advanced materials capable of operation over 2000 ℃ for future thermal protection systems application, C/C-ZrC-SiC composites were fabricated by reactive melt infiltration （RMI） wi...To meet the increasing demand for advanced materials capable of operation over 2000 ℃ for future thermal protection systems application, C/C-ZrC-SiC composites were fabricated by reactive melt infiltration （RMI） with Zr, Si mixed powders as raw materials. The structural evolution and formation mechanism of the C/C- ZrC-SiC composites were discussed, and the mechanical property of the as-prepared material was investigated by compression test. The results showed that after the RMI process, a special structure with ZrC-SiC multi-coating as outer layer and ZrC-SiC-PyC ceramics as inner matrix was formed. ZrC and SiC rich areas were formed in the composites and on the coating surface due to the formation of Zr-Si intermetallic compounds in the RMI process. Mechanical tests showed that the average compression strength of the C/C-ZrC-SiC composites was 133.86 MPa, and the carbon fibers in the composites were not seriously damaged after the RMI process.展开更多
采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭／炭复合材料。通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭／炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前...采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭／炭复合材料。通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭／炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前后的微观形貌及物相组成。结果表明:HfC的加入降低了炭／炭复合材料的线烧蚀率,其中HfC含量为6．5％(质量分数,下同)的炭／炭复合材料的线烧蚀率最低。HfC具有抑制氧化及弥补缺陷的作用,从而降低了炭／炭复合材料的热化学烧蚀和机械剥蚀。展开更多
基金This work was financially supported by the National Natural Science Foundation of China for Distinguished Young Scholars (No. 50225210) the Foundation of Aeronautic Science of China (No. 03H53044).
文摘In order to effectively employ the unique high temperature mechanical properties of carbon/carbon composite substrates, SiC coatings reinforced by SiC whiskers were prepared by pack cementation method. The effect of SiC whiskers on the oxidation resistance properties of the single-layer coating and double-layer coating was investigated. SiC whiskers in the single-layer SiC coating have little effect on the anti-oxidation property but obviously improve the thermal shock property. The double-layer coating with inner-layer reinforced coating exhibits more perfect anti-oxidation ability than the double-layer coating with SiC inner-layer coating.
基金supported by the China Postdoctoral Science Foundation(No.2012M511752)the National Basic Research Program of China(No.2011CB605801)+2 种基金the Fundamental Research Funds for the Central Universities(No. 2012QNZT004)the Freedom Explore Program of Central South University,the Open-End Fund for the Valuable and Precision Instruments of Central South University(No.CSUZC2012026)the Postdoctoral Science Foundation of Central South University
文摘To meet the increasing demand for advanced materials capable of operation over 2000 ℃ for future thermal protection systems application, C/C-ZrC-SiC composites were fabricated by reactive melt infiltration （RMI） with Zr, Si mixed powders as raw materials. The structural evolution and formation mechanism of the C/C- ZrC-SiC composites were discussed, and the mechanical property of the as-prepared material was investigated by compression test. The results showed that after the RMI process, a special structure with ZrC-SiC multi-coating as outer layer and ZrC-SiC-PyC ceramics as inner matrix was formed. ZrC and SiC rich areas were formed in the composites and on the coating surface due to the formation of Zr-Si intermetallic compounds in the RMI process. Mechanical tests showed that the average compression strength of the C/C-ZrC-SiC composites was 133.86 MPa, and the carbon fibers in the composites were not seriously damaged after the RMI process.
文摘采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭／炭复合材料。通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭／炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前后的微观形貌及物相组成。结果表明:HfC的加入降低了炭／炭复合材料的线烧蚀率,其中HfC含量为6．5％(质量分数,下同)的炭／炭复合材料的线烧蚀率最低。HfC具有抑制氧化及弥补缺陷的作用,从而降低了炭／炭复合材料的热化学烧蚀和机械剥蚀。
