Reactions in the system ZrC-ZrB2

Ordan’yan, S. S.; Unrod, V. I.

doi:10.1007/bf00807811

Cited by 23 publications

(10 citation statements)

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“…The H V value of the ZrB 2 –ZrC x N 1− x composites was lower than that of a dense ZrB 2 –ZrC x composite (about 20 GPa at indentation load of 5 N) produced by reactive hot‐pressing, because the grain sizes of the ZrB 2 and ZrC x were much smaller (about 0.6 and 0.4 μm, respectively) than that of ZrB 2 and ZrC x N 1− x in this study . Another reason for the discrepancy was that ZrB 2 and ZrC were reported to be harder than ZrN . The hardness of the directionally solidified ZrB 2 –ZrC lamellar eutectics were reported to have a maximum Knoop hardness of 24 GPa at an indentation load of 4.9 N .…”

Section: Resultscontrasting

confidence: 62%

“…Thus, the increase in hardness with composition was due to the increase in hardness from the solid solution of ZrC x N 1− x phase. The hardness of ZrC x N 1− x would increase with the x value since ZrC had a higher hardness than ZrN . The evolution of the hardness of the rod‐like eutectic composites with 50 mol% ZrB 2 could be the result of two competing mechanisms: the Hall–Petch relationship and rule‐of‐mixtures law, and generally followed a rule‐of‐mixtures type of behavior.…”

Section: Resultsmentioning

confidence: 99%

“…ZrB 2 has a hexagonal crystal structure, while ZrC and ZrN share the same face‐centered cubic crystal structures . The ZrB 2 –ZrC and ZrB 2 –ZrN both are quasi‐binary eutectic systems, and the ZrC–ZrN is a complete solid solution system of ZrC x N 1− x . Therefore, the ZrB 2 –ZrC–ZrN is expected to be a quasi‐binary eutectic system of ZrB 2 –ZrC x N 1− x .…”

Section: Introductionmentioning

confidence: 99%

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ZrB₂–ZrC_xN_1−x Eutectic Composites Produced by Melt Solidification

2015

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Ceramic eutectics are naturally occurring in‐situ composites and can offer superior mechanical properties. Here, ZrB2–ZrCxN1−x quasi‐binary ceramic eutectic composites were produced by arc‐melting a mixture of ZrB2, ZrC, and ZrN powders in an N2 atmosphere. The arc‐melted ZrB2–ZrCxN1−x composites containing 50 mol% of ZrB2 (irrespective of the ZrC/ZrN ratio) showed rod‐like eutectic structures, where ZrCxN1−x single‐crystalline rods were dispersed in the ZrB2 single‐crystalline matrices. Multiple orientation relationships between the ZrCxN1−x rods and the ZrB2 matrices were observed, and one was determined as ZrB2 { 01 1 ¯ 0 } //ZrxN1−x {111} and ZrB2 < 2 1 ¯ 1 ¯ 0 > //ZrCxN1−x < 10 1 ¯ > . The rod‐like eutectic composites had higher hardness than the hypo‐ and hypereutectic composites and the 50ZrB2–40ZrC–10ZrN (mol%) eutectic composite showed the highest Vickers hardness (Hv) of 19 GPa.

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Section: Resultscontrasting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ZrB₂–ZrC_xN_1−x Eutectic Composites Produced by Melt Solidification

2015

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“…), which might be derived from reactions between the carbon/B 4 C additive and the ZrO 2 /B 2 O 3 surface oxides (as per reactions proposed by Zhu et al and Zhang et al). These newly formed species and the unreacted additives with either very limited solubility (~2 mol%) or no intersolubility with the ZrB 2 component then present as stable secondary phase inclusions within the matrix of ZrB 2 …”

Section: Discussionmentioning

confidence: 99%

“…These newly formed species and the unreacted additives with either very limited solubility (~2 mol%) or no intersolubility with the ZrB 2 component then present as stable secondary phase inclusions within the matrix of ZrB 2 . 43,44 As seen in Table II, incorporating a small amount of additives was found to result in larger average grain sizes along with increased sintered densities, with an exception for specimens containing carbon black additive that showed decreased grain sizes. For all the additives studied (including carbon black), increasing the concentration of additive resulted in an increase in sintered density and a decrease in average grain size.…”

Section: (3) Effect Of Sintering Additivesmentioning

confidence: 97%

Pressureless Sintering of ZrB₂Prepared by Colloidal Processing: Particle Packing, Sintering Conditions, and Additives

2016

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Nonaqueous colloidal processing in cyclohexane and slip casting allowed the preparation of green ZrB2 compacts with 67.3% TD (theoretical density), which upon pressureless sintering at 2100°C densified to a final density of 92.4% TD. The effect of controllable sintering parameters (temperature, time, and heating rate) on the sintered properties of ZrB2 compacts prepared using the nonaqueous colloidal processing method was also studied, to maximize the sintered density and tailor the desired microstructure (i.e., dense final object with small grain size). The competition between pore elimination and grain growth mainly controls the final density achievable. ZrB2 compacts with maximum sintered densities of 93% TD could be achieved by controlling the sintering conditions. Finally, the use of carbon and B4C additives to improve the sintered density and microstructure of ZrB2 compacts was also investigated. The additives, compatible with colloidal processing, allowed compacts with greater sintered densities (96–98% TD) and finer grain sizes to be achieved by pressureless sintering, even at a lower temperature of 1900°C.

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