相变辅助闪烧制备Al_(2)O_(3)-ZrO_(2)纳米非晶复合材料  

Preparation of Al_(2)O_(3)-ZrO_(2)Nanostructured Amorphous Composites by Phase Transformation Assisted Flash Sintering

作　　者：王竖淮 王江林 杨永康 贾子祺 苏兴华[1] 许西庆 WANG Shuhuai;WANG Jianglin;YANG Yongkang;JIA Ziqi;SU Xinghua;XU Xiqing(School of Materials Science and Engineering,Chang’an University,Xi’an 710061,China)

机构地区：[1]长安大学材料科学与工程学院,西安710061

出　　处：《硅酸盐学报》2025年第3期658-665,共8页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(52102062);中央高校基础研究基金(CHD300102313204);西安市科技计划项目(23LLRH0004)资助。

摘　　要：纳米非晶复合材料是以纳米非晶材料为基体并析出一定纳米晶相的新型材料,具有很多特殊性能,但其制备需要庞大且昂贵的烧结设备,相比之下闪烧设备简单经济,可在较低温度实现快速致密化,为纳米非晶复合材料的制备提供新的途径。采用溶胶凝胶法制备了Al_(2)O_(3)-La_(2)O_(3)(AL)、Al_(2)O_(3)La_(2)O_(3)-ZrO_(2)(ALZ)、Al_(2)O_(3)-ZrO_(2)(AZ)3种纳米非晶粉体,通过闪烧技术制备了纳米非晶复合材料。3种体系在1000 V/cm下发生闪烧后,AZ纳米非晶复合材料具有最大结晶度(69.82%)和最高相对密度(89%)的均匀显微组织。将电场强度提升至1600 V/cm,AZ的结晶度和相对密度进一步提高至74.11%和96%。研究表明,闪烧可以加速非晶样品粉体向晶态的转变,同时相变过程促进了原子扩散和颗粒重排,对闪烧过程中的致密化起到了改善作用。AZ闪烧样品的HRTEM证实了纳米非晶结构的存在,t-ZrO_(2)、α-Al_(2)O_(3)和m-ZrO_(2)纳米晶相在非晶基质中均匀析出,纳米晶和非晶区域的平均粒径分别为8.74 nm和3.15 nm,表明相变辅助闪烧致密化可实现纳米非晶复合陶瓷材料的低温快速制备。Introduction Nanostructured amorphous composites are novel materials composed of nanostructured amorphous matrix and precipitated nanocrystalline phases.However,their preparation requires large and expensive equipment.Flash sintering(FS)ensures a rapid densification at low temperatures and offers an effective approach for the preparation of nanostructured amorphous composites with simple and economical equipment.The amorphous powders by FS show denser microstructures,compared to the crystalline powders by FS.The phase transition from a metastable phase to a stable phase during the sintering process can expedite atomic diffusion and particle rearrangement,thereby promoting structural densification.In this paper,nanostructured amorphous powders in three systems,i.e.,Al_(2)O_(3)-La_(2)O_(3)(AL),Al_(2)O_(3)-La_(2)O_(3)-ZrO_(2)(ALZ)and Al_(2)O_(3)-ZrO_(2)(AZ),were prepared by a sol-gel method and densified into dense bulks via flash sintering.The flash sintering behaviors of these different systems were compared,and the promotion of phase transformation on the densification was discussed.Methods The three systems of amorphous powders,i.e.,AL,ALZ,and AZ,were synthesized via a sol-gel method and subsequently calcined at 600℃for 1 h.Before flash sintering,the powders were consolidated into cylindrical green bodies(φ8 mm×2.3 mm)through uniaxial compression molding at 500 MPa.A platinum wire and electrodes were used to establish electrical connections between a DC power supply and the sample in electric fields of 1000 V/cm and 1600 V/cm,and a heating rate of 10℃/min.At a predetermined maximum current of 0.26 A/cm^(2),the control mode of the power supply was swiftly switched from voltage control to current control.The voltage and current both were measured by a digital electrical multimeter.After continuous energizing for 60 s,the furnace and power supply both were powered off and naturally cooled to ambient temperature.Results and discussion The powders of AL,AZ and ALZ all exhibit weak and broad scattering peaks wit

关 键 词：纳米非晶材料 闪烧 低温烧结 氧化铝-氧化锆 相变 

分 类 号：TB32[一般工业技术—材料科学与工程]