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Published byHector Cunningham Modified over 9 years ago
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Top-down approach 長庚化材系 郭修伯
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Grinding l 粗碎: n m 級 to 10 cm 以下 n Jaw crusher n Gyratory crusher
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Grinding l 中碎: n 10 cm to 1 cm 以下 ; Crushing roll
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Grinding l 中碎: n 10 cm to 1 cm 以下 ; Hammer mill & Roller mill
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Grinding l 微粉碎: n 1 cm to 10 micron 以下 ; roller mill, jet mill, ball mill, vibration mill, planetary mill Low temperature increasing 大小 ball 分佈;最適回轉數
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Grinding l 微粉碎: n 1 cm to 10 micron 以下 ; roller mill, jet mill, ball mill, vibration mill, planetary mill 40-50 % fill, several g
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Grinding l 超微粉碎: n 10 micron to 1 micron 以下 ; 介質攪拌型粉碎機, vibration mill, planetary mill
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Surface charge distribution l The distributions of ions and counter ions are controlled by n Coulomic force or electrostatic force n Entropic force or dispersion n Brownian motion l Inhomogenous distribution n double layer structure n separated by the Helmholtz plane
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Fig 2.14
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Van der Waals attraction potential l The sum of the molecular interaction for all pairs of molecules n weak force and becomes significant only at a very short distance n agglomeration of nanoparticles: the combination of van der Waals force and Brownian motion n Prevent agglomeration: electrostatic repulsion and steric exclusion
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Electrostatic repulsion stabilization Fig 2.18
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Steric exclusion stabilization l Also “polymeric stabilization” l Widely used in stabilization of colloidal dispersions n thermodynamic stabilization: particles are always redispersible n high concentration can be accommodated n not electrolyte sensitive n suitable to multiple phase systems
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Polymeric stabilization Fig 2.21
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Gas phase particle formation
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Gas phase particle formation, CVD
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Formation of particles in solutions
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Formation of particles in solutions, chemical methods
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Formation of particles in solutions, physical methods
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