氧化镁稳定氧化锆纳米粉末的制备与物相分析

Preparation and characterization of nano-powder zirconia stabilized by magnesia

以草酸为络合剂,采用溶胶–凝胶法制备一系列氧化镁稳定氧化锆粉末Zr1 xMgxO2 x（0.04≤x≤0.10）,利用X射线衍射（XRD）、场发射扫描电镜（FESEM）等分析技术对粉末进行表征。结果表明,掺杂氧化镁后,低温350~450℃煅烧产物晶型为四方相（t-ZrO2）,随煅烧温度升高,t-ZrO2逐渐向m-ZrO2转变。在550℃下煅烧时,少部分四方相转变为单斜相（m-ZrO2）,转变比例随掺杂量增加而降低。Mg2＋取代Zr4＋产生氧缺陷是ZrO2晶体结构稳定的主要因素。随煅烧温度从350℃升高到650℃,Zr0.92Mg0.08O1.92粉末中t-ZrO2晶粒尺寸从42 nm长大到100nm;随Mg掺杂量从0.04增加到0.10,t-ZrO2晶粒尺寸从110 nm减小到97.8 nm,而纳米尺寸晶粒有利于t-ZrO2稳定。

Nano-powder magnesia stabilized zirconia Zr1 xMgxO2 x powders were prepared by sol-gel process using oxalic acid as precipitant.The crystal phase composition and structure of oxide powders were determined by X-ray diffraction（XRD） and field emission scanning electron microscope（FESEM）,respectively.The results of XRD show that tetragonal phase ZrO2 and little monoclinic phase ZrO2 form at 550 ℃,while the tetragonal Zr1 xMgxO2 x forms at 350 ℃.When x is below 0.08 and with temperature increasing,part of t-ZrO2 transforms to m-ZrO2,and the ratio of transformtion decreases with increasing x value,when x is above 0.10,t-ZrO2 transformation ratio increases with increasing temperature.The generation of oxygen defect after Mg2＋ replacing Zr4＋ is the main factor to influence the stabilization of the ZrO2 crystal structure.The crystillize size of t-ZrO2 increases from 42 nm to 100 nm when temperature increases from 350 ℃ to 650 ℃,and t-ZrO2 crystillize size decreases from 110 nm to 97.8 nm with MgO-doped amount increases from 0.04 to 0.10.Nano grain size is favorable for the stability of t-ZrO2.