通过溶胶-凝胶法合成了硅酸锆包裹氧化改性炭黑(Zr Si O4/C)色料,采用XRD、色度仪和TEM等分析手段对色料进行表征。研究了改性C的球磨方式、溶剂种类和成型压力等工艺因素对Zr Si O4合成及Zr Si O4/C色料色度的影响规律。结果表明:着色...通过溶胶-凝胶法合成了硅酸锆包裹氧化改性炭黑(Zr Si O4/C)色料,采用XRD、色度仪和TEM等分析手段对色料进行表征。研究了改性C的球磨方式、溶剂种类和成型压力等工艺因素对Zr Si O4合成及Zr Si O4/C色料色度的影响规律。结果表明:着色剂C粉的形貌对包裹色料的色度影响明显,手磨过筛后的C粉呈颗粒状,分布均匀,制得的色料黑度较高,而经过振动球磨后的C呈絮状,不宜进行包裹;水溶剂会导致异质聚合Si-O-Zr键断裂,形成同质聚合,不利于包裹体Zr Si O4的低温合成,从而影响色料的呈色;过高的成型压力阻碍了Zr Si O4合成过程中的Si F4气相传质,影响了Zr Si O4的正常生长,不利于炭黑包裹和色料的发色。展开更多
The development of advanced aircraft relies on high performance thermal-structural materials,and carbon/carbon com-posites(C/C)composited with ultrahigh-temperature ceramics are ideal candidates.However,the traditiona...The development of advanced aircraft relies on high performance thermal-structural materials,and carbon/carbon com-posites(C/C)composited with ultrahigh-temperature ceramics are ideal candidates.However,the traditional routes of compositing are either inefficient and expensive or lead to a non-uniform distribution of ceramics in the matrix.Compared with the traditional C/C-ZrC-SiC composites prepared by the reactive melt infiltration of ZrSi_(2),C/C-ZrB_(2)-ZrC-SiC composites prepared by the vacuum infiltration of ZrB_(2) combined with reactive melt infiltration have the higher content and more uniform distribution of the introduced ceramic phases.The mass and linear ablation rates of the C/C-ZrB_(2)-ZrC-SiC composites were respectively 68.9%and 29.7%lower than those of C/C-ZrC-SiC composites prepared by reactive melt infiltration.The ablation performance was improved because the volatilization of B_(2)O_(3),removes some of the heat,and the more uniformly distributed ZrO_(2),that helps produce a ZrO2-SiO2 continu-ous protective layer,hinders oxygen infiltration and decreases ablation.展开更多
A toughener that can effectively improve the interlaminar toughness in carbon fiber composites is crucial for various applications.We investigated,the toughening effects of phenolphthalein-based cardo poly(ether sulfo...A toughener that can effectively improve the interlaminar toughness in carbon fiber composites is crucial for various applications.We investigated,the toughening effects of phenolphthalein-based cardo poly(ether sulfone)(PES-C)on E51/DETDA epoxy and its carbon fiber composites(CFCs).Scanning electron microscopy showed that the phase structures of PES-C/epoxy blends change from island(of dispersed phase)structures to bi-continuous structures(of the matrix)as the PES-C content increased,which is associated with reaction-induced phase separation.After adding 15 phr PES-C,the glass transition temperature(T_(g))of the blends increased by 51.5℃,and the flexural strength,impact strength and fracture toughness of the blends were improved by 41.1%,186.2%and 42.7%,respectively.These improvements could be attributed to the phase separation structure of the PES-C/epoxy sys-tem.A PES-C film was used to improve the mode-II fracture toughness(G_(IIC))of CFCs.The G_(IIC) value of the 7μm PES-C film toughened laminate was improved by 80.3%compared to that of the control laminate.The increase in G_(IIC) was attributed to cohesive failure and plastic deformation in the interleaving region.展开更多
文摘通过溶胶-凝胶法合成了硅酸锆包裹氧化改性炭黑(Zr Si O4/C)色料,采用XRD、色度仪和TEM等分析手段对色料进行表征。研究了改性C的球磨方式、溶剂种类和成型压力等工艺因素对Zr Si O4合成及Zr Si O4/C色料色度的影响规律。结果表明:着色剂C粉的形貌对包裹色料的色度影响明显,手磨过筛后的C粉呈颗粒状,分布均匀,制得的色料黑度较高,而经过振动球磨后的C呈絮状,不宜进行包裹;水溶剂会导致异质聚合Si-O-Zr键断裂,形成同质聚合,不利于包裹体Zr Si O4的低温合成,从而影响色料的呈色;过高的成型压力阻碍了Zr Si O4合成过程中的Si F4气相传质,影响了Zr Si O4的正常生长,不利于炭黑包裹和色料的发色。
文摘The development of advanced aircraft relies on high performance thermal-structural materials,and carbon/carbon com-posites(C/C)composited with ultrahigh-temperature ceramics are ideal candidates.However,the traditional routes of compositing are either inefficient and expensive or lead to a non-uniform distribution of ceramics in the matrix.Compared with the traditional C/C-ZrC-SiC composites prepared by the reactive melt infiltration of ZrSi_(2),C/C-ZrB_(2)-ZrC-SiC composites prepared by the vacuum infiltration of ZrB_(2) combined with reactive melt infiltration have the higher content and more uniform distribution of the introduced ceramic phases.The mass and linear ablation rates of the C/C-ZrB_(2)-ZrC-SiC composites were respectively 68.9%and 29.7%lower than those of C/C-ZrC-SiC composites prepared by reactive melt infiltration.The ablation performance was improved because the volatilization of B_(2)O_(3),removes some of the heat,and the more uniformly distributed ZrO_(2),that helps produce a ZrO2-SiO2 continu-ous protective layer,hinders oxygen infiltration and decreases ablation.
文摘A toughener that can effectively improve the interlaminar toughness in carbon fiber composites is crucial for various applications.We investigated,the toughening effects of phenolphthalein-based cardo poly(ether sulfone)(PES-C)on E51/DETDA epoxy and its carbon fiber composites(CFCs).Scanning electron microscopy showed that the phase structures of PES-C/epoxy blends change from island(of dispersed phase)structures to bi-continuous structures(of the matrix)as the PES-C content increased,which is associated with reaction-induced phase separation.After adding 15 phr PES-C,the glass transition temperature(T_(g))of the blends increased by 51.5℃,and the flexural strength,impact strength and fracture toughness of the blends were improved by 41.1%,186.2%and 42.7%,respectively.These improvements could be attributed to the phase separation structure of the PES-C/epoxy sys-tem.A PES-C film was used to improve the mode-II fracture toughness(G_(IIC))of CFCs.The G_(IIC) value of the 7μm PES-C film toughened laminate was improved by 80.3%compared to that of the control laminate.The increase in G_(IIC) was attributed to cohesive failure and plastic deformation in the interleaving region.
