纳米晶钇稳定氧化锆的制备及表征

以草酸盐为沉淀剂,通过化学共沉淀-高温煅烧法制备了系列钇稳定氧化锆,采用XRD分析技术对样品进行表征。结果表明,不进行钇掺杂时,ZrO2在煅烧温度较低时,晶型以t-ZrO2为主,煅烧温度提高,t-ZrO2向m-ZrO2转变,900℃时晶型已完全转变为m-ZrO2。掺杂钇后低温煅烧产物晶型为四方相,当掺杂钇的含量低于6%(摩尔分数)时,随着煅烧温度提高,少部分四方相转变为单斜相,转变比例随着掺杂量的提高而降低;掺杂钇的含量达到6%(摩尔分数)时,低温煅烧产物的晶型为四方相,随着煅烧温度的提高,晶型保持稳定。Y3+取代Zr4+产生氧缺陷是ZrO2晶体结构稳定化的主要因素。通过该方法制备的钇稳定氧化锆均为纳米晶,晶粒尺寸随着煅烧温度的提高而长大。

Preparation and Characterization of Nano-crystalline Yttria Stabilized Zirconia

The nano-crystalline yttria stabilized zirconia Zr1-xYxO2-0.5x was prepared by coprecipitation and high temperature process using oxalate as precipitator.The crystal structure of oxalate precipitate and oxide powder was determined by X-ray diffraction.The result of XRD showed that tetragonal phase ZrO2 and little monoclinic phase ZrO2 was firstly formed at 500 ℃,the t-ZrO2 was transformed to m-ZrO2 as temperature increased and the t-ZrO2 was completely transformed to m-ZrO2 at 900℃.The tetragonal phase Zr1-xYxO2-0.5 was firstly formed at 400 ℃.When x was below 0.6,part of t-ZrO2 was transformed to m-ZrO2 as temperature increased,the ratio of transform at 900℃ was decreased as x value increased.When x was above 0.6,the crystal structure kept stable as temperature increased.The oxygen defect was generated after Y3+ replaced Zr4+,and this was the main factor to influence the stabilization of the ZrO2 crystal structure.