晶界偏析GeO_(2)和TiO_(2)共掺杂对3%氧化钇稳定氧化锆陶瓷低温老化的影响

Effect of grain boundary segregation on low-temperature aging of 3%yttrium oxide stabilized zirconia ceramics co-doped with GeO_(2)and TiO_(2)

背景:近年来的研究发现,TiO_(2)和GeO_(2)共掺杂可提高氧化锆的超塑性。目的:探讨TiO_(2)和GeO_(2)共掺杂对3%氧化钇稳定氧化锆材料抗低温老化性能的影响。方法:使用机械球磨法、烘干、无压烧结制备共掺杂GeO_(2)和TiO_(2)的3%氧化钇稳定氧化锆材料,其中3%氧化钇稳定氧化锆的摩尔百分比均为98%,TiO_(2)粉末(纯度99.8%)与GeO_(2)粉末的摩尔百分比分别为1.5%,0.5%,记为1.5Ti-0.5Ge组;TiO_(2)粉末(纯度99.99%)与GeO_(2)粉末的摩尔百分比分别为1%,1%,记为1Ti-1Ge组;TiO_(2)粉末(纯度99.8%)与GeO_(2)的粉末摩尔百分比分别为0.5%,1.5%,记为0.5Ti-1.5Ge组。采用扫描透射电子显微镜、能谱仪等研究材料的微观结构;在高压釜中处理后,采用X射线衍射仪测量所有样品的转化量。结果与结论:①扫描透射电子显微镜下可见,GeO_(2)和TiO_(2)共掺3%氧化钇稳定氧化锆材料的复合粉体粒径均匀,分布在50 nm左右,颗粒形状基本呈球形,分散性好,但有少量团聚;X射线能谱仪检测显示,四价稳定剂(Ge^(4+),Ti^(4+))可以抑制氧化锆材料的低温老化效应,随着GeO_(2)掺杂量的增加,氧化锆的抗水热老化性能提高;能谱仪检测显示,随着掺杂剂含量的增加,晶界偏析程度增强,但即使Ge^(4+)的掺杂量较小,晶界偏析程度也可与掺杂量大的Ti^(4+)相媲美;②结果表明,添加GeO_(2)和TiO_(2)可提高3%氧化钇稳定氧化锆陶瓷的抗低温老化性能,其中GeO_(2)在抗低温老化方面优于TiO_(2),可作为首选。

BACKGROUND:Many recent studies have found that zirconia co-doped with TiO_(2) and GeO_(2) exhibits excellent superplasticity.OBJECTIVE:To investigate the improvement of anti-cryogenic aging properties of zirconia materials stabilized by 3%yttrium oxide co-doped with TiO_(2) and GeO_(2).METHODS:The 3%yttrium oxide stabilized zirconia material samples co-doped with GeO_(2) and TiO_(2) were prepared by mechanical ball milling,drying,and pressure free sintering.Among them,the mole percentage of 3%yttrium oxide stabilized zirconia was 98%.The mole percentages of TiO_(2) powder(purity 99.8%)and GeO_(2) powder were 1.5%and 0.5%,respectively,which was recorded as the 1.5Ti-0.5Ge group.The mole percentages TiO_(2) powder(purity)99.99% and GeO_(2) powder were 1%and 1%,respectively,which was recorded as 1Ti-1Ge group.The mole percentages of TiO_(2) powder(purity 99.8%)and GeO_(2) powder were 0.5%,1.5%,respectively,which was recorded as 0.5Ti-1.5Ge group.The microstructure of all samples was investigated by scanning transmission electron microscopy and energy spectroscopy.After treatment in an autoclave,the conversion of all samples was measured by an X-ray diffractometer.RESULTS AND CONCLUSION:(1)Scanning transmission electron microscopy results showed that the composite powders of a 3%yttrium oxide stabilized zirconia material co-doped with GeO_(2) and TiO_(2) had uniform particle size and were distributed over a 50 nm;the particle shape was basically spherical and well dispersed,but there was a small amount of agglomeration.X-ray diffractometer exhibited that the Ge^(4+),Ti^(4+) stabilizers could inhibit the low-temperature aging effect of zirconia materials.With the increase of the doping amount of GeO_(2),the low-temperature aging resistance of zirconia could be improved.Energy spectrometer detection demonstrated that with the increase of dopant content,the degree of grain boundary segregation increased,but even if the doping amount of Ge^(4+) was small,the degree of grain boundary segregation could be comparable to that of Ti^(4+) with a large amount of doping.(2)The results suggest that the addition of GeO_(2) and TiO_(2) improved 3%yttrium oxide stabilized zirconia ceramics against low-temperature aging properties.GeO_(2) is superior to TiO_(2) in resisting low-temperature aging and can be used as the first choice.