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Diffusion-Activation energy and Diffusion Equation

Diffusion-Activation energy and Diffusion Equation -...

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Diffusion Activation Energy Equilibrium Maximum distortion ∆? ° : Activation Energy for migration
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Diffusion Γ ? = ?υ exp ∆± ° ?? ? : # of surrounding sites υ : mean vibration frequency ∆² ° : activation enthalpy ∆³ ° : activation entropy ∆± ° = ∆² ° − ?∆³ ° Activation Energy
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Diffusion Γ ? = ?υ exp ∆± ° ?? ∆± ° = ∆² ° − ?∆³ ° ´ ? = 1 6 Γ ? µ 2 ´ ? = 1 6 µ 2 ?υ exp ∆³ ° ? exp ∆² ° ?? Activation Energy
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Diffusion ? ? = 1 6 ° 2 ?υ exp ∆± ² ³ exp ∆´ ² ³? ? ? = ? 0 exp µ ¶· ³? µ ¶· = ∆´ ² i.e.: ? ? increases exponentially with ? at a rate determined by the activation enthalpy (Arrhenius equation). µ ¶· : Activation enthalpy for interstitial diffusion Activation Energy
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Diffusion Activation Energy ? = ? 0 exp ? ±? Applicable to substitutional as well as interstitial diffusion
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Diffusion Activation Energy log D = −? 2.3?? + log ± 0
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Diffusion Activation Energy
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Diffusion Equation Atoms entering: ° 1 ±²?
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Diffusion-Activation energy and Diffusion Equation -...

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