Effect of Y2O3 and Yb2O3 on the microstructure and mechanical properties of silicon nitride

Lu, Horng-Hwa; Huang, Jow-Lay

doi:10.1016/s0272-8842(01)00008-6

Cited by 81 publications

(38 citation statements)

References 28 publications

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“…As one of the typical fragile brittle materials, the mechanical properties of porous Si 3 N 4 ceramics have been investigated extensively [1][2][3][4][5]7,[11][12][13]. The flexural strength has been extensively tested in the open literatures and the failure mechanisms are classified into two categories by Inagaki et al [1], which include bridging of the crack by unbroken fibrous reinforcing grains that is partially debonded from the matrix (or grain bridging) and frictional pull-out of fibrous grains (or grain pullout).…”

Section: Introductionmentioning

confidence: 99%

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Experiment and modeling on the compressive behaviors for porous silicon nitride ceramics

Liu

Han

et al. 2013

Materials Science and Engineering: A

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Section: Introductionmentioning

confidence: 99%

“…Actually, the available literatures reveal that the mechanical properties of porous Si 3 N 4 ceramics mostly depends on microstructure and the composition of grain boundary phase [11,20,21]. It is therefore essential to construct the connections between micro-parameters and the macroscopic mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Experiment and modeling on the compressive behaviors for porous silicon nitride ceramics

Liu

Han

et al. 2013

Materials Science and Engineering: A

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“…R ecent studies suggest that silicon nitride is foremost considered a prime candidate for its high‐temperature applications due to both its high flexural strength and high fracture toughness both at room temperature and in high temperatures 1–5 . The reports indicated that the flexural strength degradation of silicon nitride at a high temperature is mainly due to softening of the grain‐boundary phase 4–6 . Consequently, the refractory grain‐boundary phase is an important factor to improve the high‐temperature strength of silicon nitride.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, the refractory grain‐boundary phase is an important factor to improve the high‐temperature strength of silicon nitride. Such methods of improving the refractoriness of the grain‐boundary phase are discussed 1–7 . One method includes selecting sintering additives that form the glassy grain‐boundary phase with a high softening temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Another method to improve the high‐temperature strength of silicon nitride is to promote the crystallization of the grain‐boundary phase by applying post‐sintering heat treatment. Liu and Huang reported that the high‐temperature strength of silicon nitride sintered with yttria and alumina was improved from approximately 250–400 MPa at 1673 K by the post heat treatment 6 . However, Pierce et al 7 .…”

Section: Introductionmentioning

confidence: 99%

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Improved High‐Temperature Strength of Silicon Nitride Toughened with Aligned Whisker Seeds

Park¹,

Hahn²,

Bae³

et al. 2005

Journal of the American Ceramic Society

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The effect of the amount of the sintering additives, i.e., yttria and alumina, on the microstructure and the high‐temperature flexural strengths of silicon nitride with and without the aligned whisker seeds was examined. As the amount of the sintering additives was increased, both width and length of the grains were increased. The high‐temperature strengths of silicon nitride with and without the aligned seeds were increased and decreased, respectively, according to the increase of the amount of the sintering additives. When both 4.8 wt% yttria and 2.2 wt% alumina were added to silicon nitride with the aligned whisker seeds, the experimental results indicated that it had three times the flexural strength as silicon nitride without the seeds at 1673 K. During the high‐temperature flexure testing, observations did not indicate yielding present in the samples with the aligned whisker seeds, while it was present in samples without the whisker seeds. The reinforcing grains growing from the whisker seeds aligned perpendicular to the crack propagation direction acted as effective obstacles to the crack propagation and improved the fracture toughness.

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Mechanical properties andin vitrobioactivity of silicon nitride ceramics withSiO₂,CaO, andMgOadditions

2021

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Silicon nitride ceramics with SiO 2 , CaO, and MgO as sintering aids were investigated in view of biomedical applications. In the current study, samples with four different compositions were pressureless sintered at 1750 C for 1 h under a nitrogen atmosphere. The samples were evaluated concerning densification, microstructure, mechanical properties, and in vitro bioactivity. Microstructures with elongated β-Si 3 N 4 grains dispersed in an intergranular phase and with densities from 78.77 to 97.14% of the theoretical density were obtained. Higher contents of SiO 2 resulted in the best densification and mechanical properties. Besides, replacements of CaO by MgO in the initial compositions affected Young's modulus and in vitro bioactivity.Considering the samples with relative density higher than 94.14%, those with lower values of Young's modulus had lower SiO 2 /MgO ratios. After immersion in SBF (Simulated Body Fluid), the samples with high porosity and/or partial replacements of CaO by MgO had their surfaces coated with a layer rich in calcium and phosphorus, morphologically similar to hydroxyapatite. Hence, producing silicon nitride ceramics with the potential to be used as orthopedic implants must consider ideal amounts of additives. In this article, the best combination of mechanical properties and mineralization capability was reached by the composition with low content of MgO, and high content of SiO 2 and CaO.

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Effect of Y2O3 and Yb2O3 on the microstructure and mechanical properties of silicon nitride

Cited by 81 publications

References 28 publications

Experiment and modeling on the compressive behaviors for porous silicon nitride ceramics

Experiment and modeling on the compressive behaviors for porous silicon nitride ceramics

Improved High‐Temperature Strength of Silicon Nitride Toughened with Aligned Whisker Seeds

Mechanical properties andin vitrobioactivity of silicon nitride ceramics withSiO₂,CaO, andMgOadditions

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Effect of Y2O3 and Yb2O3 on the microstructure and mechanical properties of silicon nitride

Cited by 81 publications

References 28 publications

Experiment and modeling on the compressive behaviors for porous silicon nitride ceramics

Experiment and modeling on the compressive behaviors for porous silicon nitride ceramics

Improved High‐Temperature Strength of Silicon Nitride Toughened with Aligned Whisker Seeds

Mechanical properties andin vitrobioactivity of silicon nitride ceramics withSiO2,CaO, andMgOadditions

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Mechanical properties andin vitrobioactivity of silicon nitride ceramics withSiO₂,CaO, andMgOadditions