基底表面状态对异质形核影响的实验研究  

Experimental Researches on Heterogeneous Nucleation Behavior with Different Surface Conditions

作　　者：王猛 王修星[1] 郑浩勇[1] 黄卫东[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造技术》2011年第5期626-629,共4页Foundry Technology

基　　金：国家自然科学基金项目50901061和50771083;国家重点基础研究发展计划项目2004CB619107;凝固技术国家重点实验室自主研究课题资助项目02-TZ-2008和36-TP-2009资助

摘　　要：对铸型型壁形核点密度的研究,在铸造领域有着重要意义。从润湿性角度出发,通过水在基底上的润湿角来计算基底的表面能,并引入具有标度不变性的分形维数以定量表征粗糙表面粗糙程度,研究形核基底表面状态对NH4Cl晶粒异质形核行为的影响规律。结果表明,表面能和微观形貌对基底表面的润湿性和形核特性具有显著影响。刻蚀获得的LY12基底表面微观形貌丰富,呈现出明显的分形特性,该表面具有超亲水性,可获得较高的NH4Cl晶粒异质形核密度;而经低表面能的氟硅烷修饰后则具有超疏水性,其表面的NH4Cl晶粒形核密度明显降低。It is of great significance to study the density of nucleation sites on the surface of casting mould in the research of casting process.In the present paper,substrate surface energy was calculated by measuring the contact angle of water on the substrate and the roughness of the surface was quantitatively characterized by fractal dimension parameters.Effects of substrate surface roughness on the nucleation behaviors of NH4Cl crystal was analyzed experimentally,the results indicate that： surface energy and micro-morphology have significant influences on the wet ability and nucleation properties of the substrate.The etched LY12 substrate surface has a complicated micro-morphology and exhibits fractal characteristics apparently.The as-etched surface in a state of high surface energy exhibits super-hydrophilicity and gives a high nucleation density in the followed nucleation experiments.When the surface is treated with 1H,1H,2H,2H-Perfluorooctyltrime-thoxysilane,the surface energy of the substrate decreases,and the surface become super-hydrophobicity and gives a lower nucleation density in the nucleation experiments.

关 键 词：形核 润湿性 表面能 分形维数 

分 类 号：TG214[金属学及工艺—铸造]