Preparation of high hardness and high fracture toughness Si3N4 ceramics by combining in-situ nitriding and hot-press sintering

IF 3.8 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Vacuum Pub Date : 2025-05-11 DOI:10.1016/j.vacuum.2025.114402

Shiao Wu , Yang Li , Yueming Li , Fuyuan Zheng , Zhongyi Zhao , Xiangqing Kong , Guorui Zhao

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引用次数: 0

Abstract

Preparation Si₃N₄ ceramics with high hardness and high fracture toughness is a challenge. In this work, Si₃N₄ ceramics with high hardness (18.35 ± 0.40 GPa) and high fracture toughness (8.54 ± 0.26 MPa m^1/2) were obtained by in-situ nitriding of Si and Y powders and hot-press sintering. By controlling Y content, Si₃N₄ powders with different α-Si₃N₄ ratios were obtained, which in turn regulated grain size and morphology of Si₃N₄ ceramics after sintering. Addition of Y introduces Y-Si-O-N crystalline phase into nitrided powder, which transitions to Y₂Si₂O₇ during subsequent sintering. Y₂Si₂O₇ phase reduces bulk hardness but introduces residual stresses at interface, promotes grain elongation, and improves fracture toughness through crack bridging, stretching, and crack deflection mechanisms. In addition, atomic-scale microstructural analysis reveals coherent interfaces were formed between both Si₃N₄/SiO₂/Y₂Si₂O₇ as well as Si₃N₄/Si₂N₂O, with crystallographic orientation relationships of (100) Si₃N₄//(100) SiO₂//(−111) Y₂Si₂O₇ and [010] Si₃N₄//[001] SiO₂//[12–1] Y₂Si₂O₇ as well as (100) Si₃N₄//(020) Si₂N₂O and [010] Si₃N₄//[−102] Si₂N₂O. These in-situ generated coherent interfaces significantly enhance mechanical properties and reliability of samples, ensuring both high hardness and high fracture toughness.

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原位氮化与热压烧结相结合制备高硬度、高断裂韧性Si3N4陶瓷

制备具有高硬度和高断裂韧性的氮化硅陶瓷是一个挑战。本研究采用原位氮化和热压烧结的方法制备了高硬度（18.35±0.40 GPa）和高断裂韧性（8.54±0.26 MPa m2 /2）的Si3N4陶瓷。通过控制Y含量，可以得到不同α-Si3N4比例的Si3N4粉体，从而调控烧结后Si3N4陶瓷的晶粒尺寸和形貌。Y的加入使Y- si - o - n晶相进入氮化粉末中，在随后的烧结过程中转变为Y2Si2O7。Y2Si2O7相降低了体硬度，但在界面处引入了残余应力，促进了晶粒伸长率，并通过裂纹桥接、拉伸和裂纹挠曲机制提高了断裂韧性。此外，原子尺度的微观结构分析表明，Si3N4/SiO2/Y2Si2O7和Si3N4/Si2N2O之间形成了相干界面，晶体取向关系为（100）Si3N4//(100) SiO2//(−111)Y2Si2O7和[010]Si3N4//[001] SiO2//[12-1] Y2Si2O7，晶体取向关系为（100）Si3N4//(020) Si2N2O和[010]Si3N4//[−102]Si2N2O。这些原位生成的相干界面显著提高了试样的力学性能和可靠性，保证了试样的高硬度和高断裂韧性。

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来源期刊

Vacuum 工程技术-材料科学：综合

CiteScore

6.80

自引率

17.50%

发文量

审稿时长

34 days

期刊介绍： Vacuum is an international rapid publications journal with a focus on short communication. All papers are peer-reviewed, with the review process for short communication geared towards very fast turnaround times. The journal also published full research papers, thematic issues and selected papers from leading conferences. A report in Vacuum should represent a major advance in an area that involves a controlled environment at pressures of one atmosphere or below. The scope of the journal includes: 1. Vacuum; original developments in vacuum pumping and instrumentation, vacuum measurement, vacuum gas dynamics, gas-surface interactions, surface treatment for UHV applications and low outgassing, vacuum melting, sintering, and vacuum metrology. Technology and solutions for large-scale facilities (e.g., particle accelerators and fusion devices). New instrumentation ( e.g., detectors and electron microscopes). 2. Plasma science; advances in PVD, CVD, plasma-assisted CVD, ion sources, deposition processes and analysis. 3. Surface science; surface engineering, surface chemistry, surface analysis, crystal growth, ion-surface interactions and etching, nanometer-scale processing, surface modification. 4. Materials science; novel functional or structural materials. Metals, ceramics, and polymers. Experiments, simulations, and modelling for understanding structure-property relationships. Thin films and coatings. Nanostructures and ion implantation.