3D carbon fiber needled felt and polycarbosilane-derived SiC coating were selected as reinforcement and interfacial coating,respectively,and the sol-impregnation-drying-heating(SIDH)route was used to fabricate C/Al2O3...3D carbon fiber needled felt and polycarbosilane-derived SiC coating were selected as reinforcement and interfacial coating,respectively,and the sol-impregnation-drying-heating(SIDH)route was used to fabricate C/Al2O3 composites.The effects of Si C interfacial coating on the mechanical properties,oxidation resistance and thermal shock resistance of C/Al2O3 composites were investigated.It is found that the fracture toughness of C/Al2O3 composites was remarkably superior to that of monolithic Al2O3 ceramics.The introduction of SiC interfacial coating obviously improved the strengths of C/Al2O3 composites although the fracture work diminished to some extent.Owing to the tight bonding between SiC coating and carbon fiber,the C/SiC/Al2O3 composites showed much better oxidation and thermal shock resistance over C/Al2O3 composites under static air.展开更多
A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned no rmally to the grinding wheel surface by laminating Al sheets...A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned no rmally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5 nm (Ry26 nm) was achieved.展开更多
The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces ...The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces were created from a smooth stainless steel and aluminium sheets and two other stainless steel sheets with different textured surfaces. All surfaces were coated with carbon nanofiber alcohol solutions in order to generate coatings of variable compositions using mixtures of isopropanol, water and a commercial carbon nanofibre. The optimum concentration of carbon nanofiber in coatings was obtained to produce superhydrophobic surfaces. A general trend of increasing hydrophobicity was observed for coated surfaces as compared to the bare substrate. Individual contact angles were dependent on the nature of the underlying substrate, relative surface pattern, and roughness. Overall wetting properties were dependent upon composition and micro scale roughness of the coatings.展开更多
文摘3D carbon fiber needled felt and polycarbosilane-derived SiC coating were selected as reinforcement and interfacial coating,respectively,and the sol-impregnation-drying-heating(SIDH)route was used to fabricate C/Al2O3 composites.The effects of Si C interfacial coating on the mechanical properties,oxidation resistance and thermal shock resistance of C/Al2O3 composites were investigated.It is found that the fracture toughness of C/Al2O3 composites was remarkably superior to that of monolithic Al2O3 ceramics.The introduction of SiC interfacial coating obviously improved the strengths of C/Al2O3 composites although the fracture work diminished to some extent.Owing to the tight bonding between SiC coating and carbon fiber,the C/SiC/Al2O3 composites showed much better oxidation and thermal shock resistance over C/Al2O3 composites under static air.
文摘A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned no rmally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5 nm (Ry26 nm) was achieved.
文摘The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces were created from a smooth stainless steel and aluminium sheets and two other stainless steel sheets with different textured surfaces. All surfaces were coated with carbon nanofiber alcohol solutions in order to generate coatings of variable compositions using mixtures of isopropanol, water and a commercial carbon nanofibre. The optimum concentration of carbon nanofiber in coatings was obtained to produce superhydrophobic surfaces. A general trend of increasing hydrophobicity was observed for coated surfaces as compared to the bare substrate. Individual contact angles were dependent on the nature of the underlying substrate, relative surface pattern, and roughness. Overall wetting properties were dependent upon composition and micro scale roughness of the coatings.
