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