无机材料学报2025，Vol.40Issue(7)：817-825,9.DOI:10.15541/jim20250060
ZrB2-HfSi2复相陶瓷显微组织及其核-周结构形成机制
ZrB2-HfSi2 Ceramics:Microstructure and Formation Mechanism of Core-rim Structure
摘要
Abstract
In recent years,ZrB2,as a representative material of ultra-high temperature ceramics(UHTCs),has become an important candidate material system for components of new generation aerospace vehicles.However,its practical application is limited by difficulties in material preparation and processing of complex components.This study aims to optimize sintering process of ZrB2-based UHTCs by introducing HfSi2 as a sintering aid,specifically addressing the challenge of densification caused by low intrinsic diffusion coefficient of traditional ZrB2 ceramics.The research focuses on elucidating formation mechanism of core-rim structured borides and their role in enhancing densification of ZrB2-HfSi2 ceramics.Dense ZrB2-HfSi2 ceramics were successfully fabricated via hot-press sintering at 1600℃.The results reveal that softening of HfSi2 phase during sintering effectively fills interparticle gaps,thereby facilitating low-temperature densification.Furthermore,during the holding stage,interdiffusion of Hf and Zr atoms through a dissolution-reprecipitation mechanism facilitates formation of a core-rim structured ZrB2/(Zr,Hf)B2 composite.This core-rim structure consists of ZrB2 core encased by a(Zr,Hf)B2 rim,characterized by a fully coherent interface(hexagonal P6/mmm symmetry)with a low lattice mismatch(<5%),ensuring interfacial stability.The ZrB2-HfSi2 ceramic exhibits a compressive strength of(1333±83)MPa,a Vickers hardness of(15.86±0.72)GPa,and a fracture toughness of(2.01±0.36)MPa·m1/2.The ZrB2-HfSi2 ceramic demonstrates typical intergranular fracture behavior,with only a limited number of cleavage planes displaying core-rim structural features.These findings provide critical insights into low-temperature sintering of UHTCs and underscore potential of core-rim structures in advancing the preparation of high-performance ceramics.关键词
ZrB2-HfSi2陶瓷/HfSi2烧结助剂/致密化/核-周结构/共格界面Key words
ZrB2-HfSi2 ceramic/HfSi2 sintering aid/densification/core-rim structure/coherent interface分类
通用工业技术引用本文复制引用
魏志帆,陈国清,祖宇飞,刘渊,李明浩,付雪松,周文龙..ZrB2-HfSi2复相陶瓷显微组织及其核-周结构形成机制[J].无机材料学报,2025,40(7):817-825,9.基金项目
国家自然科学基金(52075073)National Natural Science Foundation of China(52075073) （52075073）
