添加剂对氧化锆四方相纯度及晶粒尺寸的影响

Influence of additives on the tetragonal phase purity and grain size of zirconia

背景:有关实验参数对氧化锆粒子直径及其中四方相氧化锆比例影响的研究很多,但在合成过程中添加剂(乙二胺四乙酸、丙三醇)对氧化锆这两方面的影响尚无统一结论。目的:探讨添加剂乙二胺四乙酸、丙三醇对氧化锆粒子直径及其中四方相氧化锆的影响规律。方法:以硝酸锆为原料,加入添加剂乙二胺四乙酸或丙三醇,用氨水调节pH值,通过水热法合成6种氧化锆样品,其中Zr^(4+)∶乙二胺四乙酸∶丙三醇的摩尔比例分别为1∶0∶0,1∶1∶0,1∶0∶1,1∶0.5∶0.5,1∶0.25∶0.75,1∶0.75∶0.25,设置编号分别为1-6。利用X射线衍射仪对制备样品进行表征,分析2种添加剂对氧化锆粒子直径及其中四方相氧化锆比例的影响规律。结果与结论:(1)3号样品为纯四方相氧化锆,粒子直径最大;其余5个样品均含有四方相、单斜相两种晶相,且四方相含量大于单斜相;3-6号样品粒子直径大于1,2号样品;1,3号样品四方相含量高于2,4,5,6号样品;(2)结果表明,乙二胺四乙酸可降低氧化锆粒子直径,也会降低氧化锆四方相比例;丙三醇可提高氧化锆四方相比例,增大氧化锆粒子直径。

BACKGROUND:Numerous studies have been made on the experimental parameters that influence the grain size of zirconia crystal and purity of tetragonal phase of zirconia.Until now,however,there is no unified conclusion on the influence of additives(ethylenediaminetetraacetic acid or glycerol)on the grain size of zirconia crystal and purity of tetragonal phase of zirconia.OBJECTIVE:To investigate the influence of additives(ethylenediaminetetraacetic acid or glycerol)on the grain size of zirconia crystal and purity of tetragonal phase of zirconia.METHODS:Nitrates were adopted as raw materials,ethylenediaminetetraacetic acid or glycerol was adopted as additives,and ammonium hydroxide was chosen to adjust the pH of the solution.Then six kinds of zirconia were synthesized using hydrothermal method.The mole ratio of Zr4+:ethylenediaminetetraacetic acid:glycerol were 1:0:0,1:1:0,1:0:1,1:0.5:0.5,1:0.25:0.75,1:0.75:0.25,and the samples were numbered 1-6 and characterized by X-ray diffraction.Afterwards,the influence of additives(ethylenediaminetetraacetic acid or glycerol)on the grain size and purity of tetragonal phase of zirconia was analyzed.RESULTS AND CONCLUSION:Sample No.3 was pure tetragonal zirconia and had the largest grain size.The other five samples contained two kinds of crystalline phases:tetragonal and monoclinic phases.Meanwhile,the content of tetragonal phase was higher than that of monoclinic phase.The grain size of samples No.3-6 was larger than that of samples No.1 and 2.The content of tetragonal phase of samples No.1 and 3 was higher than that of samples No.2,4,5,and 6.Our experimental data indicate that ethylenediaminetetraacetic acid could decrease the grain size and proportion of tetragonal phase of zirconia,while glycerol could increase the proportion and grain size of tetragonal phase of zirconia.