Effect of Mo2C addition on the mechanical properties and oxidation resistance of ZrB2-SiC ceramics

Vedel, D. V.; Grigoriev, O. N.; Mazur, Piotr; Osipov, A.E.; Brodnikovs’kyi, M. P.; Silvestroni, Laura

doi:10.1016/j.jallcom.2021.160398

Cited by 12 publications

(6 citation statements)

References 29 publications

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“…MoSi 2 or Mo‐based phases were not detected inside the fiber‐enriched bulk. It was reported that the reaction between MoSi 2 and ZrB 2 during heat treatment results in the formation of a (Zr,Mo)B 2 solid solution, which also reveals a core–shell structure, 1,36 and the formation of a transient liquid phase 5,11,12,37 . Consequently, a small amount of the soluble Mo within this composite is captured inside this solid solution.…”

Section: Resultsmentioning

confidence: 89%

“…It was reported that the reaction between MoSi 2 and ZrB 2 during heat treatment results in the formation of a (Zr,Mo)B 2 solid solution, which also reveals a coreshell structure, 1,36 and the formation of a transient liquid phase. 5,11,12,37 Consequently, a small amount of the soluble Mo within this composite is captured inside this solid solution. However, the major fraction of the soluted Mo within this reference sample is dissolved in the transient liquid phase, which diffuses toward the fiber-enriched bulk.…”

Section: Microstructure Of the Baseline Reference Samplementioning

confidence: 99%

“…Another critical aspect in aerospace application is the high weight, due to the high density of the matrix materials based on ZrB 2 with 6 g/cm 3 , which must be lowered. The addition of MoSi 2 proved to be beneficial for the sinterability, 5 the strength retention at high temperatures, and for the oxidation resistance of ZrB 2 composites [6][7][8][9][10] up to the high-temperature regime of ≥1600 • C, 11,12 while the incorporation of SiC fibers considerably lowers the overall density. Moreover, the addition of 10-30 vol% SiC or C short fibers increases fracture toughness above 6 MPa √ m, [13][14][15] being attributed to crack deflection and fiber bridging mechanisms and, for high-volume fraction of fibers, to pull-out [16][17][18] additionally improving the oxidation resistance.…”

Section: Introductionmentioning

confidence: 99%

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Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB₂‐based ultra‐high temperature ceramics

2022

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A ZrB2‐based ceramic, containing short Hi‐Nicalon SiC fibers, was fabricated with a Mo‐impermeable buffer layer sandwiched between bulk and the outermost oxidation resistant ZrB2–MoSi2 layer, in order to prevent inward Mo diffusion and associated fiber degradation reactions. This additional layer consisted of ZrB2 doped with either Si3N4 or with the polymer‐derived ceramics (PDCs) SiCN and SiHfBCN. Scanning electron microscopy imaging and elemental mapping via energy‐dispersive X‐ray spectroscopy showed that this tailored sample geometry provides an effective diffusion barrier to prevent the SiC fibers from deterioration due to reactions with Mo or Mo‐compounds. In contrast, the structure of the SiC fibers in a reference sample without buffer layer is strongly degraded by MoSi2 diffusion into the fiber core. The comparison of the three buffer‐layer systems showed a moderate alteration of the fiber structure in the case of Si3N4 addition, whereas in the PDC‐doped samples hardly any structural change within the fibers was observed. A stepwise reaction mechanism is deduced, based on the continuous progression of a reaction zone that propagates toward the ZrB2–MoSi2 top layer. The progression of such a reaction zone as a consequence of the different eutectic melts forming in the different layers, that is, first in the SiC‐fiber‐containing bulk, then in the buffer layer itself, and finally in the top layer at high temperature, allows for an effective separation of the ZrB2–MoSi2 top layer from the SiC fibers. Subsequent oxidation at 1500°C and 1650°C for 15 min did not affect the efficiency of all three buffer layers, since no structural changes regarding buffer layer and fibers were observed, as compared to the non‐oxidized samples.

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Section: Resultsmentioning

confidence: 89%

Section: Microstructure Of the Baseline Reference Samplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB₂‐based ultra‐high temperature ceramics

2022

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“…When a load is applied, sliding the heterogeneous phase boundaries facilitates plastic deformation before fracture, resulting in increased strain with improved bond strength. [37][38][39] The dense microstructure at the interface in Figure 10E confirms that the fracture took place at the interlayer, which was made up of Ni-rich and Mo-rich phases (Figure 10F). Furthermore, there are no crack or graphite phases at the fracture site.…”

Section: Mechanical Performance Of Jointsmentioning

confidence: 78%

Effect of Mo addition on interfacial microstructure and mechanical property of SiC joint brazed by an Ni–Si filler

Kamal,

Shukla,

Shinde

et al. 2024

J Am Ceram Soc.

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Ni‐based alloys provide good brazing filler characteristics for the many applications of SiC ceramics. Nevertheless, the presence of graphite is unavoidable in the reaction between Ni and SiC, leading to a significant degradation of the mechanical properties of the joint. This study investigates the effect of Mo in Ni–30Si alloy on the brazing of SiC at 1300°C, to regulate interfacial reactions and reduce residual stresses by decreasing overall coefficient of thermal expansion (CTE) values throughout the brazing process. The addition of Mo up to 8 at.% efficiently suppresses graphite accumulation by converting it into Mo2C + Ni3Mo3C phases and lowering the CTE to 5.4 × 10−6/°C. When the Mo loading exceeds 12 at.%, the interactions between the filler and SiC are reduced as a result of the non‐homogeneous dispersion of Mo. The experimental findings indicate that the joint without graphite has a lap shear strength of 107 MPa, which is nearly three times greater than the joint with graphite. Thermodynamic analyses are performed to provide a comprehensive understanding of the underlying mechanisms responsible for the formation of distinct phases in brazed joints.

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“…Silicide additives [37][38][39][40][41][42][43][44][45][46][47][48][49] such as ZrSi 2 and MoSi 2 can significantly improve the oxidation resistance of composites, increase fracture toughness, and reduce sintering temperature, so they are considered excellent additives. In addition to SiC, carbide additives [50][51][52][53][54][55][56][57][58][59][60][61][62] such as B 4 C, WC, and Mo 2 C can improve the mechanical properties, oxidation, and ablation resistance of the composites, by optimizing microstructure and removing impurities. For example, (Zr,W)B 2 core-edge substructure formed by the addition of WC, significantly improved the mechanical properties at high temperature.…”

Section: Introductionmentioning

confidence: 99%

Effects of refractory metal additives on diboride‐based ultra‐high temperature ceramics: A review

Meng

Fang

Wang³

et al. 2023

Int J Applied Ceramic Tech

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Diboride-based ultra-high temperature ceramics (UHTCs) are a special class of ceramics with excellent comprehensive properties, which have extensive potential applications in extreme environments. However, their practical applications are limited, mainly due to the poor fracture toughness and thermal shock resistance. Refractory metals have high melting points, good ductility, and high toughness, which have huge potential to improve the properties of diboridebased ceramics. As a special class of additives, they have been adopted to promote densification, improve microstructure, and properties. However, diboride-based ceramics containing refractory metals have not received adequate attention due to relatively weak practical effects on property improvement. The present review highlights the progress and existing problems of transition metal diborides with refractory metal additives, including W, Ta, Mo, Nb, Hf, V, Cr, and Zr, focusing mainly on the microstructure change and property improvements, followed by challenges and possible future development strategies.

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Effect of Mo2C addition on the mechanical properties and oxidation resistance of ZrB2-SiC ceramics

Cited by 12 publications

References 29 publications

Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB₂‐based ultra‐high temperature ceramics

Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB₂‐based ultra‐high temperature ceramics

Effect of Mo addition on interfacial microstructure and mechanical property of SiC joint brazed by an Ni–Si filler

Effects of refractory metal additives on diboride‐based ultra‐high temperature ceramics: A review

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Effect of Mo2C addition on the mechanical properties and oxidation resistance of ZrB2-SiC ceramics

Cited by 12 publications

References 29 publications

Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB2‐based ultra‐high temperature ceramics

Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB2‐based ultra‐high temperature ceramics

Effect of Mo addition on interfacial microstructure and mechanical property of SiC joint brazed by an Ni–Si filler

Effects of refractory metal additives on diboride‐based ultra‐high temperature ceramics: A review

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Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB₂‐based ultra‐high temperature ceramics

Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB₂‐based ultra‐high temperature ceramics