Crack profiles under a Vickers indent in silicon nitride ceramics with various microstructures

Miyazaki, Hiroyuki; Hyuga, Hideki; Yoshizawa, Yu‐ichi; Ohji, Tatsuki

doi:10.1016/j.ceramint.2009.07.016

Cited by 15 publications

(4 citation statements)

References 18 publications

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“…The slopes of the lines for Si 3 N 4 -A and Si 3 N 4 -B (Figure 6) have an approximate value of 0.14 and 0.15 for both types of nitrides and with a heat treatment after 300 °C, respectively; all the slopes of the lines are closer to the value of 1/6 than the value of 1/2 , so it is concluded that the silicon nitride develops predominantly in the load range under study a system of radial cracks for both compositions and regardless of whether they have undergone changes or not by the effect of temperature Chicot et al (2004). It should be noted that this same system of cracks coincides with the results of the work done by researchers (Lube, 2002;Miyazaki et al, 2010;Ordoñez, 2013), who reported that from the 98 N of applied load on the indentation the radial median crack system for this type of ceramic material is developed. Once it was known which crack system predominated, it was analyzed which of the equations formulated for this type of system, represents the best results of fracture toughness in comparison to those reported in the literature.…”

Section: Fracture Toughness (Kc)supporting

confidence: 79%

Determination of fracture toughness and elastic module in materials based silicon nitride

Rodriguez

Minchala-Marquino

Romero

et al. 2019

iit

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The knowledge of the mechanical properties of any material subjected to loads is necessary for its use in structural applications. Silicon nitride (Si3N4) ceramics are well-known materials used in engineering applications due to their outstanding combination of high strength and fracture toughness. The most studied mechanical properties of Si3N4 are hardness, fracture toughness and mechanical resistance. Recent advances in the production processes that incorporate high purity rare earth elements as sintering additives have improved these mechanical properties. Using Vickers indentation method, the elastic module and fracture toughness of Si3N4 based materials modified with La2O3, Y2O3 and Al2O3 were determined as a function of the cracking system type that prevails under the effect of load. The results indicate that adding rare earth to the matrix increased the fracture toughness the Si3N4 base ceramic Samples containing La2O3+Y2O3 showed higher values of fracture toughness than the ones with Al2O3+La2O3, regardless of the equation used in the calculations. Meanwhile the elastic module decrease approximately 100 GPa for both types of nitrides by the effect of the temperature.

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Section: Fracture Toughness (Kc)supporting

confidence: 79%

Determination of fracture toughness and elastic module in materials based silicon nitride

Rodriguez

Minchala-Marquino

Romero

et al. 2019

iit

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“…These values are in good agreement with Vickers hardness values commonly measured on hot-pressed silicon nitride materials. 21,22 The decrease of Vickers hardness in samples containing 20%LAS could be related to both its relatively low densification and high content of amorphous phase. Despite of we expected based on the level of densification, the mechanical properties of 5%LAS-sa sample are significantly lower than that classically measured on hot-pressed or gaspressure sintered silicon nitride materials, or even the values measured in 20%LAS material.…”

Section: Structural Mechanical and Thermal Characterization Of Selecmentioning

confidence: 98%

Spark Plasma Sintering of fine alpha-silicon nitride ceramics with LAS for spatial applications

Reverón

Blanchard²,

Vitupier³

et al. 2011

Journal of the European Ceramic Society

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“…Many additive combinations have been added to Si 3 N 4 but no information is available on chromium oxide as an additive for Si 3 N 4 systems. Chromium oxide, Cr 2 O 3 , has interesting properties such as refractoriness, corrosion resistance, and very high hardness.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Chromium Oxide on the Sintering Behavior of Silicon Nitride

Alem

Pugh

2012

Int J Applied Ceramic Tech

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In this study, pressureless sintering of silicon nitride via the addition of chromium oxide was investigated. Silicon nitride samples containing additives from the Cr–Cr2O3–SiO2 system were sintered under different conditions. The phase transformation, the degree of densification and the in situ reactions between Si3N4 and chromium compounds were investigated and the reactions were validated thermodynamically. It was found that Si3N4 reacts with Cr2O3 and Cr and these in situ reactions lead to Si3N4 decomposition and consequently formation of a series of chromium silicides including Cr3Si, Cr5Si, and CrSi2. Due to the presence of chromium silicides as liquid phases during sintering, the α‐Si3N4 to β‐Si3N4 phase transformation started around 1400°C and was completed around 1800°C. On the other hand, densification of Si3N4 samples with chromium oxide addition was not observed. The participation of Cr2O3 in these in situ reactions prevents sufficient formation of chromium silicate and leads to insufficient liquid phase with poor wettability during sintering, resulting in poor densification.

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Crack profiles under a Vickers indent in silicon nitride ceramics with various microstructures

Cited by 15 publications

References 18 publications

Determination of fracture toughness and elastic module in materials based silicon nitride

Determination of fracture toughness and elastic module in materials based silicon nitride

Spark Plasma Sintering of fine alpha-silicon nitride ceramics with LAS for spatial applications

The Influence of Chromium Oxide on the Sintering Behavior of Silicon Nitride

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