Research Progress on Toughening Technologies of Silicon Nitride Ceramics

doi:10.16552/j.cnki.issn1001-1625.2026.0172

Abstract

Abstract:

As a high-performance structural engineering ceramics， Si₃N₄ has emerged as an ideal candidate material for demanding applications in advanced sectors such as aerospace， automotive， electronics， and medical technology， owing to its outstanding mechanical properties， wear resistance， thermal shock resistance， and chemical stability. However， the inherent high brittleness of Si₃N₄-based ceramics greatly restricts their application in a wider range of engineering fields. Over the years， researchers worldwide have conducted extensive research on the insufficient toughness in Si₃N₄-based ceramics. This paper systematically reviews the research progress on improving the toughness of Si₃N₄ ceramics： firstly， starting from the key factors affecting fracture toughness， it elaborates on the influence of powder properties of raw materials， sintering aid system， sintering process， and grain morphology and orientation distribution on the toughness of Si₃N₄ ceramics； based on this， it conducts in-depth analysis and discussion of the main toughening strategies and mechanisms. Finally， the paper outlines the future development trends and key breakthrough directions for high-toughness Si₃N₄ ceramics.

Key words: Si₃N₄ ceramics, toughening mechanism, microstructure, self-toughening, second-phase toughening, structural toughening, mechanical property

CLC Number:

TQ174

NIE Jingkai, HOU Dong, ZOU Jianming, CHEN Tian, ZHANG Yiming, HAN Yu, HE Qiang. Research Progress on Toughening Technologies of Silicon Nitride Ceramics[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(8): 2850-2862.

Figures/Tables 11

Fig.1 Microstructure formation of Si3N4 ceramics with addition of fine-coarse α-Si3N4 mixed powder［14］

Fig.2 Schematic illustration of synthesis process of Si3N4 ceramics with multiple RE2O3 as sintering additives［27］

Fig.3 Diagram of texture evolution mechanisms for different high-pressure sintered Si3N4 ceramics［32］

Fig.4 Grain-oriented Si3N4 ceramic materials fabricated via strong magnetic field alignment：（a） perpendicular to the orientation plane，（b） parallel to the orientation plane［36］

Fig.5 Preparation methods for Si3N4 ceramics materials with grain orientation distribution：（a） hot processing method；（b） template grain growth method

Fig.6 Influence mechanism of grain orientation on fracture toughness of Si3N4 ceramics

Fig.7 Toughening mechanisms of Si3N4 ceramics：（a） crack deflection， bridging， and grain pull-out， etc［42］；（b） layered structure［43］

Fig.8 Microstructure of Si3N4 containing 5% （mass fraction） β-Si3N4 seed crystals［49］

Fig.9 Synergistic toughening mechanism of Si3N4 ceramics by β-Si3N4 whisker and MXene composite phase［53］

Fig.10 （a） SEM image of depicting layered surface of a marine organism’s shells；（b） SEM image of imitating shell pearl layer structure ceramic sample［77］

Table 1 Comprehensive comparison of different toughening methods

增韧方式	核心增韧机理	实施难度	工艺成本	韧性提升范围/（MPa·m^1/2）	对其他力学性能影响	主要局限性
晶须/纤维增韧	桥接、拔出、偏转	较高（需控制分散性、界面结合）	较高	6.60~10.36	易降低强度和硬度	晶须易团聚，界面结合差，易脱黏
相变增韧	应力诱导相变	较高（严控含量与烧结温度）	中等	8.70~10.05	提高强度，易降低高温性能	高温易生成杂质相，含量过高易团聚
颗粒弥散增韧	裂纹偏转、钉扎	中等（控制颗粒分散与反应）	中等	8.00~9.39	部分会降低高温稳定性	颗粒易团聚，界面反应难控制
结构增韧	裂纹偏转、扭转，延长扩展路径	高（结构精准，制备难度大）	高	10.71~11.22	易降低强度	制备工艺复杂，量产难度大
自增韧	裂纹偏转、晶粒拔出和桥接	中等（调控烧结助剂/烧结参数等）	较低	7.60~13.50	提高强度，轻微降低硬度	晶粒形貌调控难度大，易出现过度生长

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