Pivalic Acid-Ethanol 및 Succinonitrile-Salol 계에서의 수지상정 선단의 형상 (Dendrite Tip Shapes of Pivalic Acid-Ethanol and Succinonitrile-Salol Systems)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 49권 / 7호 / 570 ~ 576페이지
· 저자명 : 석명진, 박영민, 오승탁, 장시영

초록

The shape of a dendrite tip has long been approximated by a paraboloid of revolution, but many attempts have been made as well to more accurately match the dendrite tip profile using other mathematical functions: power function, 4th order polynomial, and hyperbolic function. In the present work, dendrite tip shapes were matched by parabolic function. The differences between the dendrite tip shapes of pivalic acid(PVA)-ethanol(Eth) and succinonitrile(SCN)-salol systems,characterized by anisotropic and isotropic solid-liquid interfacial properties, respectively, were quantitatively treated using shape parameters. The PVA-Eth system showed a slightly higher Z/R value than the SCN-salol system, their Z/R values lying in the range 2-4. (Z is the distance from the tip beyond which the parabolic fit starts to deviate from the profile, and R the tip radius.)λ_P is the distance from the tip beyond which side branching starts to appear, and is larger in the PVA-Eth system than the SCNsalol system. λ_P is different for both sides of the 2-dimensional dendrite profile. The difference of λ_P between both sides of the dendrite is larger for PVA-Eth system than for SCN-salol, implying that the dendrite of PVA-Eth is less symmetric than that of SCN-salol.

영어초록

The shape of a dendrite tip has long been approximated by a paraboloid of revolution, but many attempts have been made as well to more accurately match the dendrite tip profile using other mathematical functions: power function, 4th order polynomial, and hyperbolic function. In the present work, dendrite tip shapes were matched by parabolic function. The differences between the dendrite tip shapes of pivalic acid(PVA)-ethanol(Eth) and succinonitrile(SCN)-salol systems,characterized by anisotropic and isotropic solid-liquid interfacial properties, respectively, were quantitatively treated using shape parameters. The PVA-Eth system showed a slightly higher Z/R value than the SCN-salol system, their Z/R values lying in the range 2-4. (Z is the distance from the tip beyond which the parabolic fit starts to deviate from the profile, and R the tip radius.)λ_P is the distance from the tip beyond which side branching starts to appear, and is larger in the PVA-Eth system than the SCNsalol system. λ_P is different for both sides of the 2-dimensional dendrite profile. The difference of λ_P between both sides of the dendrite is larger for PVA-Eth system than for SCN-salol, implying that the dendrite of PVA-Eth is less symmetric than that of SCN-salol.

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