The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pre...The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.展开更多
Two critical parameters:Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain size.Both the roughness and the vertical distance evolution along the surface of deposi...Two critical parameters:Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain size.Both the roughness and the vertical distance evolution along the surface of deposited TiO_(2)film are affected by the crystallinity.The optimal crystallinity of TiO_(2)was deposited at the temperature of 350℃.The TiCl4 concentration effectively changed the grain size.However,the high flow rate of fluidizing gas and optimal gas–solid ratio(<0.11 m^(3)/(kg h))restricted the change of TiCl_(4)concentrations in fluidized bed reactor.In this case,the grain size of the deposited TiO_(2)film was about 55 nm.Depending on the grain size,the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO_(2)concentration.Finally,the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.展开更多
The effects of superficial gas velocity and mechanical stirring speed on the precise regulation of flow regimes for cohesive SiO2 powders(mean diameter is 16μm)were experimentally investigated in a stirring-assisted ...The effects of superficial gas velocity and mechanical stirring speed on the precise regulation of flow regimes for cohesive SiO2 powders(mean diameter is 16μm)were experimentally investigated in a stirring-assisted fluidized bed.The results showed that compared with the agglomerates formed in the non-assisted fluidization of cohesive SiO2 powders,the introduction of mechanical stirring could effectively reduce the size of agglomerates and well disperse the agglomerates during fluidization.The best regulation range of agglomerate particulate fluidization can be achieved at 600 rpm when agglomerate sizes were reduced to below 200μm.Further investigation based on the operational phase diagram revealed that transformations of flow regimes were dominated by both stirring speed and gas velocity.The stirring applied enlarges the operational range of agglomerate particulate fluidization(APF)with a delayed onset of bubbling for cohesive particles.However,the exorbitant speed increases the collision velocity and contact area between small agglomerates,which results in the formation of unstable agglomerates and the whirlpool of powder.展开更多
An efficient fluidization process intensification method was proposed to prepare carbon nanotube(CNT)-enhanced high-performance SiO anodes for lithium-ion batteries.The introduction of graphite particles decreased bon...An efficient fluidization process intensification method was proposed to prepare carbon nanotube(CNT)-enhanced high-performance SiO anodes for lithium-ion batteries.The introduction of graphite particles decreased bonding among SiO particles,inhibiting agglomerate growth and enhancing fluidization.The(SiO+G)/CNTs composites were synthesized by fluidized bed chemical vapor deposition with the CNTs grown in-situ,which ensured uniform dispersion and superior anchoring of the CNTs.The in-situ-grown CNTs and stacked graphite ensured excellent structural stability and conductivity.The synthesized(SiO+G)/CNTs delivered a stable reversible capacity of 466 mAh g^(−1) after 125 cycles and a capacity of∼200 mAh g^(−1) at 2 A g^(−1).The charging results indicated that the 3D network structure comprising CNTs and graphite not only effectively buffered the electrode expansion but also greatly improved mechanical flexibility.展开更多
基金the support from National Natural Science Foundation of China (22208355, 22178363 and 21978300)the financial support and mica samples from Changzi Wu and RIKA technology CO., LTD.
文摘The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.
基金support from National Natural Science Foundation of China(grant Nos.22208355,21978300 and 22178363).
文摘Two critical parameters:Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain size.Both the roughness and the vertical distance evolution along the surface of deposited TiO_(2)film are affected by the crystallinity.The optimal crystallinity of TiO_(2)was deposited at the temperature of 350℃.The TiCl4 concentration effectively changed the grain size.However,the high flow rate of fluidizing gas and optimal gas–solid ratio(<0.11 m^(3)/(kg h))restricted the change of TiCl_(4)concentrations in fluidized bed reactor.In this case,the grain size of the deposited TiO_(2)film was about 55 nm.Depending on the grain size,the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO_(2)concentration.Finally,the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.
基金The authors are grateful to the support by the National Natural Science Foundation of China(Grant Nos.21908227,21736010 and 22178363).
文摘The effects of superficial gas velocity and mechanical stirring speed on the precise regulation of flow regimes for cohesive SiO2 powders(mean diameter is 16μm)were experimentally investigated in a stirring-assisted fluidized bed.The results showed that compared with the agglomerates formed in the non-assisted fluidization of cohesive SiO2 powders,the introduction of mechanical stirring could effectively reduce the size of agglomerates and well disperse the agglomerates during fluidization.The best regulation range of agglomerate particulate fluidization can be achieved at 600 rpm when agglomerate sizes were reduced to below 200μm.Further investigation based on the operational phase diagram revealed that transformations of flow regimes were dominated by both stirring speed and gas velocity.The stirring applied enlarges the operational range of agglomerate particulate fluidization(APF)with a delayed onset of bubbling for cohesive particles.However,the exorbitant speed increases the collision velocity and contact area between small agglomerates,which results in the formation of unstable agglomerates and the whirlpool of powder.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.21736010,51602313,51801201,11805227)Key Research Program of Nanjing IPE Institute of Green Manufacturing Industry(No.E0010704)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.ZDBS-LY-JSC041).
文摘An efficient fluidization process intensification method was proposed to prepare carbon nanotube(CNT)-enhanced high-performance SiO anodes for lithium-ion batteries.The introduction of graphite particles decreased bonding among SiO particles,inhibiting agglomerate growth and enhancing fluidization.The(SiO+G)/CNTs composites were synthesized by fluidized bed chemical vapor deposition with the CNTs grown in-situ,which ensured uniform dispersion and superior anchoring of the CNTs.The in-situ-grown CNTs and stacked graphite ensured excellent structural stability and conductivity.The synthesized(SiO+G)/CNTs delivered a stable reversible capacity of 466 mAh g^(−1) after 125 cycles and a capacity of∼200 mAh g^(−1) at 2 A g^(−1).The charging results indicated that the 3D network structure comprising CNTs and graphite not only effectively buffered the electrode expansion but also greatly improved mechanical flexibility.
