摘要
为了改善纳米CeO2在Zn-Al类共晶合金中的分散性,采用超声液相包覆法对纳米CeO2进行表面活性剂表面包覆改性,并用AES测定了包覆层的厚度,用TEM研究了CeO2的团聚状况,用TGA分析了有机物包覆层的炭化温度范围,最后用FE-SEM观察了CeO2在复合材料中的分散情况。结果表明,包覆在纳米CeO2表面的厚度约为20 nm的表面活性剂层提高了微粒的分散性,而且该包覆层在495℃时已经炭化。热力学计算的结果也表明,炭化层能与氧化膜反应,该反应提高了CeO2与基体间的润湿性,并使其均匀分布在基体合金中。
Surface coating modification was carried out by ultrasonic agitation in organic solution with surfactant, in order to improve the dispersion of nano-CeO2 particulates in eutectic-like Zn-Al alloy. The coating effects, including covering thickness, carbonization temperature of covering layer and aggregation status of CeO2 particulates, were characterized by means of AES, thermal-gravimetric analysis （TGA） and TEM, respectively. Then, the dispersion of CeO2 in nano- CeOEp/Zn-4.5% Al-RE composites was observed by FE-SEM. The results showed that the thickness of the covering surfactant layer, which improves particulates＇ dispersion, was about 20 nm, and that a carbonization came into being on the nano-CeO2 surface at 495 ℃. Moreover, from classical thermodynamic point of view, reactions between the carbonization layer and zinc oxide, which can remove the block of oxygenation film coated on CeO2 and promote the wettability between CeO2 and the alloy, may take place on the CeO2 surface. As a result, nano-CeO2 particulates were dispersed homogeneously in the alloy
出处
《中国稀土学报》
CAS
CSCD
北大核心
2007年第3期355-359,共5页
Journal of the Chinese Society of Rare Earths
基金
江苏省高技术项目资助(2001026)
关键词
纳米CEO2
表面改性
分散性
炭化
稀土
nano-CeO2
surface modification
dispersion
carbonization
rare earths
