Lightweight and high-strength textured fibrous Si_(3)N_(4)3D scaffold see de d withβ-Si3 N4 particles prepared via freeze casting  

作　　者：Qiang Zhi Shan Zhao Baoqiang Hou Nanlong Zhang Feng Li Bo Wang Jianfeng Yang 

机构地区：[1]State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China [2]Xi’an Chaoma Technology Co.Ltd.,Xi’an 710025,China

出　　处：《Journal of Materials Science & Technology》2024年第27期75-86,共12页材料科学技术(英文版)

基　　金：supported by the National Natural Science Foundation of China(Nos.U2066216 and 52372068);the Na-tional Key R&D Program of China(Nos.2017YFB0310300 and 2017YFB0903800);the China Postdoctoral Science Foundation(No.2020M672248).

摘　　要：Highly porous Si_(3)N_(4)ceramics with unidirectionally aligned pore channels are gaining significant attention across various fields due to their outstanding functional capabilities.However,achieving high strength in such unidirectional highly porous Si_(3)N_(4)ceramics remains challenging.Herein,we design and fabricate a novel β-Si_(3)N_(4)scaffold composed of directionally aligned lamellar walls with a textured microstructure by directionally freeze casting ofα-Si_(3)N_(4)suspensions with fine elongatedβ-Si_(3)N_(4)seeds addition,followed by liquid phase sintering.During the sintering,the scaffold exhibited anisotropic shrinkage,and fibrousβ-Si_(3)N_(4)grains were synthesized through epitaxial growth on the seeds preferentially oriented or the nuclei originated fromα-Si_(3)N_(4)powders,resulting in the grains aligned parallel to lamellar walls and bridged the walls.Seed additions of 7 to 15 wt%were beneficial for the optimized distribution of the two types of β-Si_(3)N_(4)grains,which contributed to the excellent resistance to bucking-induced fracture for the walls.Compared with other unidirectional porous Si_(3)N_(4)prepared by freeze-casting in the literature,the Si_(3)N_(4)scaffold exhibited out st anding compressive strength,ranging from 2.8 to 22.0 MPa,as the porosity decreased from 94.4%to 88.0%and the density increased from 175 to 365 mg/cm^(3).The lightweight and strong Si_(3)N_(4)scaffolds are promising candidates for engineering applications in harsh environments.

关 键 词：LIGHTWEIGHT Fibrous Si3 N4 scaffold Seeds Directional freeze-casting High strength 

分 类 号：TG1[金属学及工艺—金属学]