放电等离子体烧结制备纳米非晶Al_(2)O_(3)-La_(2)O_(3)-ZrO_(2)三元共晶氧化物  

Preparation of Nanostructured-Amorphous Al_(2)O_(3)-La_(2)O_(3)-ZrO_(2)Ternary Eutectic Oxides by Spark Plasma Sintering

作　　者：王江林 李杰 李玉 李琳琳 苏兴华[1] 赵鹏[1] 许西庆 WANG Jianglin;LI Jie;LI Yu;LI Linlin;SU Xinghua;ZHAO Peng;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》2024年第9期2942-2949,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(CHD300102312406);西安市科技计划项目(23LLRH0004)。

摘　　要：纳米非晶材料是由纳米非晶颗粒以及颗粒间非晶界面构成的新型材料,表现出很多独特性能,但其制备往往需要>1 GPa的高压来完成致密化。本工作采用溶胶凝胶法制备了较宽过冷液相区(844~914℃)、平均粒径为11.6 nm的Al_(2)O_(3)-La_(2)O_(3)-ZrO_(2)(ALZ)纳米非晶粉体,并通过放电等离子烧结在875~1000℃条件下制备ALZ材料。结果表明,在875、900、927℃和1000℃烧结体相对密度分别达87.6%、98.3%、96.6%和91.5%,其中,在900℃、50 MPa条件下烧结样品具有最大的相对密度和均匀的显微组织,在STEM-BF和HRTEM下观察到了纳米晶相从非晶相基质中析出现象,纳米压痕测试样品的平均纳米硬度和杨氏模量分别为12.0 GPa和159.9 GPa。上述各烧结体相对密度大小主要与ALZ纳米非晶粉末在各温度下结晶度变化,引起粉末黏性流动改变,从而影响致密化进程有关。875℃烧结中La_(0.28)Zr_(0.72)O_(1.86)结晶度较大阻碍了非晶粉末的黏性流动;而在875~900℃会发生La_(0.28)Zr_(0.72)O_(1.86)向结晶度较小La_(2)(Zr_(2)O_(7))的相变,这有利于黏性流动;927℃和1000℃烧结的样品结晶度进一步增大不利于黏性流动。Introduction Nanostructured amorphous materials represent a novel class of materials characterized by nanostructured amorphous particles and amorphous interfaces between particles.Due to the nanometer Scales,amorphous disorder,controllable atomic and electronic structure,this kind of material exhibits numerous unique properties distinct from conventional materials.Recently,Scholars diScovered that composites composed of nanostructured amorphous materials as the matrix with precipitated nanocrystals exhibited excellent mechanical properties.However,densification of both nanostructured amorphous materials and nanostructured amorphous composites was primarily achieved through ultra-high-pressure forming.During ultra-high-pressure forming,the plastic deformation of nanostructured amorphous powder under high pressure enabled amorphous particles to contact each other,extrude pores,and diffused through interfaces to form new interfaces.However,these studies required high-pressure forming equipment,and the associated costs constrained further applications.In contrast to the ultra-high-pressure molding mentioned earlier,Rosenflanz et al.employed viScous sintering to consolidate amorphous powder within the supercooled liquid region.This method utilized amorphous powder with low viScosity above the glass transition temperature(T_(g))and its viScous flowed under external pressure to fill the pores between particles,thereby achieving densification.This approach only required 34 MPa pressure,effectively circumventing the unrealistically high pressures previously required for amorphous material preparation.However,crystallization during viScous sintering may impede the viScous flow of amorphous powder,necessitating a sufficiently wide kinetic window between the glass transition temperature(T_(g))and crystallization temperature(Tx)to achieve densification.To address this issue,Rosenflanz et al.again employed an alumina-rare earth oxide system(Al_(2)O_(3)-Re_(2)O_(3))to modulate the polyhedral structure of Al-O,regulated the glas

关 键 词：纳米非晶材料 放电等离子体烧结 过冷液相区 氧化铝-氧化镧-氧化锆 纳米压痕测试 

分 类 号：TB32[一般工业技术—材料科学与工程]