Preparation and characterization of SiO_2 non-catalytic nucleation coating for the solidification of undercooled melt  

作　　者：XI Zengzhe, YAO Xi and ZHANG Liangying(Functional Materials Research Laboratory of Tongji University, Shanghai 200092, China) 

出　　处：《Progress in Natural Science:Materials International》2003年第2期125-129,共5页自然科学进展·国际材料（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 59995520);the University Key Studies Project of Shanghai

摘　　要：SiO2 non-catalytic nucleation films were coated onto a ceramic substrate and the inner surface of a ceramic crucible by the Sol-Gel method.The surface morphology of the coatings was characterized with an atomic force microscope and a scanning electronic microscope.The non-catalytic effect of the coating on the heterogeneous nucleation of metal melts was tested through measuring the nucleation undercooling.Investigation results indicated that the prepared coating could act as a baffle-wall to prevent the metal melt from nucleating heterogeneously on the inner surface of the crystalline crucible.The tiny holes with a diameter below 2μm and heaves on the coating surface have no evident effect on the undercooling of metal melts.For a poly-layer coating,the super-layer can cover the cracks in the sublayers,which prevents the cracks in the coating from spreading in the direction vertical to the coating layers and thus eliminates the effect of cracks on the coating.SiO_2 non-catalytic nucleation films were coated onto a ceramic substrate and the inner surface of a ceramic crucible by the Sol-Gel method. The surface morphology of the coatings was characterized with an atomic force microscope and a scanning electronic microscope. The non-catalytic effect of the coating on the heterogeneous nucleation of metal melts was tested through measuring the nucleation undercooling. Investigation results indicated that the prepared coating could act as a baffle-wall to prevent the metal melt from nucleating heterogeneously on the inner surface of the crystalline crucible. The tiny holes with a diameter below 2 μm and heaves on the coating surface have no evident effect on the undercooling of metal melts. For a poly-layer coating, the super-layer can cover the cracks in the sublayers, which prevents the cracks in the coating from spreading in the direction vertical to the coating layers and thus eliminates the effect of cracks on the coating.

关 键 词：high undercooling catalytic nucleation non-crystalline coating SOL-GEL BISMUTH atomic force microscope. 

分 类 号：O613.72[理学—无机化学]