Laminated HfC–SiC ceramics produced by aqueous tape casting and hot pressing

Xiang, Liuyi; Cheng, Laifei; Lan, Shi; Yin, Xiaowei; Zhang, Litong

doi:10.1016/j.ceramint.2015.07.075

Cited by 15 publications

(7 citation statements)

References 31 publications

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“…This value is higher than those reported for isotropic HfC or HfC ceramic composites measured by Vickers indentation test . Although some other HfC based composites have been reported to possess a higher fracture toughness, they either had the good property only in a perpendicular direction or used heavy metals as the secondary phase, which increases the total weight and degrades the needed high‐temperature durability of ceramics.…”

Section: Resultsmentioning

confidence: 65%

“…Hafnium carbide (HfC) exhibits high thermodynamic stability with a melting point of ~3900°C, high hardness and Young’ s modulus, as well as good thermomechanical properties at ultra high temperature . Therefore, it is considered as a promising material for applications of high‐temperature electrodes, cutting tools, rocket nozzles, nuclear reactor rods, space/air craft and thermal‐field emitters Nevertheless, HfC exhibits a low fracture toughness (1.73‐3.40 MPa m 1/2 ), which can limit its structural applications in extreme environments . An effective way to enhance the fracture toughness of HfC is to incorporate secondary phase materials, such as silicon carbide (SiC) rods, BN, SiC ceramics, refractory metal (Tungsten) to form cermets and other high‐temperature carbides, as attempted in some previous studies .…”

Section: Introductionmentioning

confidence: 99%

“…An effective way to enhance the fracture toughness of HfC is to incorporate secondary phase materials, such as silicon carbide (SiC) rods, BN, SiC ceramics, refractory metal (Tungsten) to form cermets and other high‐temperature carbides, as attempted in some previous studies . Cheng et al developed the HfC–SiC/graphite composites, which exhibit a high fracture toughness (9.1 ± 0.5 MPa m 1/2 ), however only in the direction perpendicular to their anisotropic lamellar microstructure. HfC–W cermets have a high fracture toughness of 13.7 ± 0.7 MPa m 1/2 , but at a cost of a higher weight and a lower ablation resistance .…”

Section: Introductionmentioning

confidence: 99%

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High fracture toughness of HfC through nano‐scale templating and novel sintering aids

Hao

Guo

et al. 2018

J Am Ceram Soc

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An approach to improve the sintering ability and the fracture toughness of hafnium carbide (HfC) ceramic by designing a unique composite structure is reported. The uniform and ultra‐fine HfC nanoparticles (~300 nm) are synthesized at 1450°C by vacuum carbonization reaction with the glucose‐derived hydrothermal precursor as a carbon source and template. HfC ceramic sintered with a SiCN sintering aid of 15 vol. % possesses a beneficial three‐dimensional network microstructure composed of inter‐penetrating phases of carbon, SiC and HfC with varied stoichiometry at multi‐length scales. The obtained HfC exhibits a higher fracture toughness of 5.5 MPa m1/2, which can be attributed to the unique composite structure able to promote stress releases in the crack tip and enhance the resistance to crack propagation.

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Section: Resultsmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High fracture toughness of HfC through nano‐scale templating and novel sintering aids

Hao

Guo

et al. 2018

J Am Ceram Soc

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“…However, to our knowledge, the dispersion behaviors of HfC nanopowder in any solvents have not been studied, and the preparation of highly concentrated HfC‐based nano slurries has been rarely reported in the literatures. The preparation of aqueous HfC‐SiC slurries with binder and plasticizer were mentioned in tape casting process in the literature …”

Section: Introductionmentioning

confidence: 99%

Dispersion behavior of HfC‐based nanopowders in ethanol

Zhao

Lee

2019

Int J Applied Ceramic Tech

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The dispersion behavior of two different types of ultrafine HfC-based powders in ethanol was investigated using polyethyleneimine (PEI) as a dispersant. The first type was synthesized by carbothermal reduction using a modified spark plasma sintering technique (d50: 125 nm). For the 10 wt% HfC suspensions, the highest zeta potential value (67.7 mV), the least sediment after sedimentation test for one day, and finest particle sizes were obtained when the concentration of PEI was 2.0 wt%.The concentrated HfC slurries with a solid loading of 40 vol% were achieved using 1.0 wt% PEI. The second type was mixing the HfC powder with HfSi2-C additives using a high-energy ball milling. The concentrated HfC slurry containing 20 wt% of HfSi2-C sintering additives was prepared up to 50 vol% solid loading using 0.50 wt% PEI. This is the first report for producing highly concentrated HfC-based nano slurries, which were highly suitable for the wet process of ultrahigh-temperature ceramic matrix composites (UTHCMCs). K E Y W O R D Sdispersion behavior, Hafnium carbide, ultrahigh-temperature ceramic matrix composites

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“…The HfC ceramic also is an ultrahigh-temperature ceramic with a high melting point (about 3900 °C), high hardness, high electrical conductivity, and high elastic modulus and chemical stability [ 10 , 11 , 12 ]. HfC is a potential candidate material for aerospace applications, owing to its high melting point and low self-diffusion coefficient.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of ZrB2–HfC Ceramics Influenced by HfC Addition

2018

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ZrB2–HfC ceramics have been fabricated using the liquid phase sintering technique at a sintering temperature as low as 1750 °C through the addition of Ni. The effects of HfC addition on the microstructure and mechanical properties of ZrB2–based ceramics have been investigated. These ceramics were composed of ZrB2, HfC, Ni, and a small amount of possible (Zr, Hf)B2 solid solution. Small HfC grains were distributed among ZrB2 grain boundaries. These small grains could improve the density of ZrB2–based ceramics and play a pinning role. With HfC content increasing from 10 wt % to 30 wt %, more HfC grains were distributed among ZrB2 grain boundaries, leading to weaker interface bonding among HfC grains; the relative density and Vickers hardness increased, and flexural strength and fracture toughness decreased. The weak interface bonding for 20 and 30 wt % HfC contents was the main cause of the decrease in both flexural strength and fracture toughness.

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Laminated HfC–SiC ceramics produced by aqueous tape casting and hot pressing

Cited by 15 publications

References 31 publications

High fracture toughness of HfC through nano‐scale templating and novel sintering aids

High fracture toughness of HfC through nano‐scale templating and novel sintering aids

Dispersion behavior of HfC‐based nanopowders in ethanol

Microstructure and Mechanical Properties of ZrB2–HfC Ceramics Influenced by HfC Addition

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