摘要
针对纳米粉体制备过程中团聚问题,研究了微波干燥和烘箱干燥两种不同的干燥方式对共沉淀法制备的纳米ZrO-2粉体粒径、团聚程度、干燥时间及烧结体密度等的影响．结果表明,采用微波干燥不仅可以大大缩短干燥所需时间,而且有利于减弱纳米ZrO_2粉体的团聚和团聚强度,制得粒径小、团聚强度低和烧结活性高的纳米ZrO_2粉体,生坯经过1500℃、2h烧结,烧结密度可达到理论密度的97．3%．在分析微波干燥原理的基础上,提出了纳米粉体微波干燥“爆裂”模型,由于水是一种强极性分子,在微波干燥过程中首先受热汽化产生大量水蒸气,水蒸气受热膨胀使ZrO_2干凝胶“爆裂”成为极其微小的碎片,内部水分直接以气体形式排除,不仅大大缩短了生产周期,也有利于减弱纳米ZrO_2粉体的团聚和团聚强度．
Two different drying methods, microwave and oven drying, and their effect on particle size, aggregation intensity, drying time and sintering density of nano ZrO2 powders prepared by coprecipitation method were studied. It is found that the microwave drying way can not only shorten drying time but also reduce aggregation intensity of nano ZrO2 powders. Nano ZrO2 powders with small particle size, low aggregation intensity and high sintering activity are easily synthesized by this method. The sintering density of the powders can reach 97.3% of its theoretically density after heat treatment at 1 500℃ for 2 h. On the basis of qualitative analysis on microwave drying principle, the burst model of microwaves drying on nano ZrO2 powders is founded. Since water is a kind of strong polar molecule and firstly heated, the water is vaporized and produces a large amount of water vapor during the microwave drying process. Such quick expansion of water vapor results in that ZrO2 drying gel bursts into many tiny fragments. The internal water removes directly in the form of gas during the drying process, which not noly shortens production period, but is favorable to decrease the aggregation intensity of nano ZrO2 powders.
出处
《天津大学学报》
EI
CAS
CSCD
北大核心
2006年第B06期333-336,共4页
Journal of Tianjin University(Science and Technology)
基金
天津市科技攻关资助项目(043182311).
关键词
纳米ZRO2粉体
微波干燥
团聚状态
烧结特性
nano ZrO2 powders
microwave drying
aggregation state
sintering characteristic
