摘要
本文选用NH4Cl和H2O过饱和二元溶体为研究对象,研究其在稳恒电场作用下溶体中游离晶的重熔规律及晶体生长规律.利用显微镜感光器件(CCD)及智能通讯测温仪表,对实验过程进行实时照片拍摄和实时温度记录.结果表明:电场的Joule Heat效应为决定性因素,使得NH4Cl溶体温度场显著变化,导致糊状区的游离晶重熔明显;NH4Cl在凝固时会自然形成电阻梯度,当在垂直于NH4Cl晶体的凝固方向上施加外加电场时,Joule热可造成附加的温度梯度,温度梯度方向与原溶体的正温度梯度方向一致,电场加载后会提高溶体的温度梯度,有利于促进固液界面的稳定性.
A binary supersaturated solution of NH4C1 and H20 was selected to investigate the remelting of free faceted NH4C1 crystals in mushy zone under a steady electric field and the influence of the electric field on crystal growth. The Charge Coupled Device （CCD） in microscope and a temperature instrument with communication to computer were utilized to snap the real time profile of crystals and record the temperature data respectively. Experimental results show that the thermal field of the solution is affected significantly by Joule Heat, which leads to the consequent remehing of free crystals in mushy zone. When NH4C1 is solidifying, there is an electrical resistance gradient to emerge which will result in an extra thermal gradient whose direction agrees with that of the original positive gradient. It implies that application of electric field will intensify the thermal gradient in the binary solution, which conduces to the stabilization of solid/liquid interface.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2011年第2期144-148,共5页
Materials Science and Technology
基金
教育部新世纪优秀人才支持计划资助项目(NCET-08-0164)
