Pivalic Acid-Ethanol 및 Succinonitrile-Salol 계에서의 수지상정 선단의 형상

• Published in: 대한금속·재료학회지, 49(7) Vol. 49; no. 7; pp. 570 - 576
• Main Authors: 석명진, Myung Jin Suk, 박영민, Young Min Park, 오승탁, Sung Tag Oh, 장시영, Si Young Chang
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 20.07.2011; 대한금속·재료학회
• Subjects: anisotropy; crystal growth; dendrite tip morphology; interfaces; solidification; 재료공학
• ISSN: 1738-8228; 2288-8241

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.) λP 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. λP is different for both sides of the 2-dimensional dendrite profile. The difference of λP 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.