The secondary reinforcement,crbon whiskers,may grow on the surface of parent rein- forcement,carbon fibres,by chemical vapour growth from acetylene using Fe salt as catalyzer.The optimal growing temperature is about 1...The secondary reinforcement,crbon whiskers,may grow on the surface of parent rein- forcement,carbon fibres,by chemical vapour growth from acetylene using Fe salt as catalyzer.The optimal growing temperature is about 1000℃,and while the concentra- tion of catalytic solution is appropriate,the carbon whiskers may deposite uniformly and link each other on the parent carbon fibre surface.If the temperature or concentration is too high,the coarse clusters of carbon may deposite on the fibre surface.The mechanism of carbon whisker growth is believed that the carbon atoms in vapour phase dissolve in the Fe salt drops over fibres,then the solid carbon grains precipitate on the fibre surface.展开更多
In order to tackle the shortcomings of high brittleness,hard graphitization,and poor oxidation resistance resulted from carbonization of phenolic resin of Mg O- C refractories, effects of 2 mass% spherical Ni, and2 ma...In order to tackle the shortcomings of high brittleness,hard graphitization,and poor oxidation resistance resulted from carbonization of phenolic resin of Mg O- C refractories, effects of 2 mass% spherical Ni, and2 mass% spherical Ni plus 7. 5 mass% Al composite powder on microstructure of the secondary carbon in Mg O- C refractories matrix were investigated. The results show that a large number of carbon whiskers form after the carbonization of phenolic resin with Ni powder;in the Mg O- C refractories matrix with only Ni powder,the carbon microspheres form at all treatment temperatures and change slightly with the temperature rising;the carbon whiskers begin to generate in the specimens with composite powder at 1 000 ℃,the diameter of the carbon whiskers is about 0. 4- 0. 5 μm,and the length is about 3- 4 μm,and the formed carbon whiskers increase gradually with the temperature rising.展开更多
The impact toughness and compressive strength of concrete added with calcium carbonate whisker are studied.It is found that calcium carbonate whisker can significantly improve the impact energy consumption at failure ...The impact toughness and compressive strength of concrete added with calcium carbonate whisker are studied.It is found that calcium carbonate whisker can significantly improve the impact energy consumption at failure of 55℃steam cured concrete,but has limited impact on 90℃steam cured concrete.At the same time,SEM,XRD and LF-NMR were used to study the micro morphology,hydration product components and pore structure of the concrete,and the mechanism of the influence of calcium carbonate whisker on the impact toughness and compressive strength of concrete was analyzed.展开更多
文摘The secondary reinforcement,crbon whiskers,may grow on the surface of parent rein- forcement,carbon fibres,by chemical vapour growth from acetylene using Fe salt as catalyzer.The optimal growing temperature is about 1000℃,and while the concentra- tion of catalytic solution is appropriate,the carbon whiskers may deposite uniformly and link each other on the parent carbon fibre surface.If the temperature or concentration is too high,the coarse clusters of carbon may deposite on the fibre surface.The mechanism of carbon whisker growth is believed that the carbon atoms in vapour phase dissolve in the Fe salt drops over fibres,then the solid carbon grains precipitate on the fibre surface.
文摘In order to tackle the shortcomings of high brittleness,hard graphitization,and poor oxidation resistance resulted from carbonization of phenolic resin of Mg O- C refractories, effects of 2 mass% spherical Ni, and2 mass% spherical Ni plus 7. 5 mass% Al composite powder on microstructure of the secondary carbon in Mg O- C refractories matrix were investigated. The results show that a large number of carbon whiskers form after the carbonization of phenolic resin with Ni powder;in the Mg O- C refractories matrix with only Ni powder,the carbon microspheres form at all treatment temperatures and change slightly with the temperature rising;the carbon whiskers begin to generate in the specimens with composite powder at 1 000 ℃,the diameter of the carbon whiskers is about 0. 4- 0. 5 μm,and the length is about 3- 4 μm,and the formed carbon whiskers increase gradually with the temperature rising.
基金Funded by the National Key R&D Program of China(No.2017 YFB0310001)National Natural Science Foundation of China(Nos.51772226 and 51972249)。
文摘The impact toughness and compressive strength of concrete added with calcium carbonate whisker are studied.It is found that calcium carbonate whisker can significantly improve the impact energy consumption at failure of 55℃steam cured concrete,but has limited impact on 90℃steam cured concrete.At the same time,SEM,XRD and LF-NMR were used to study the micro morphology,hydration product components and pore structure of the concrete,and the mechanism of the influence of calcium carbonate whisker on the impact toughness and compressive strength of concrete was analyzed.
