Microstructure and mechanical properties of boron suboxide ceramics prepared by pressureless microwave sintering

Demirskyi, Dmytro; Vasylkiv, Oleg

doi:10.1016/j.ceramint.2016.05.151

Cited by 11 publications

(1 citation statement)

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“…Owing to the abnormal strength behavior of NbB 2 bulks after SPS observed in Figure , we attempted to post anneal the specimens mainly to equilibrate the thermal stresses accumulated during the SPS consolidation. This post annealing was conducted at 1300°C using a high‐temperature cell and a 24 GHz microwaves, as described in detail in . Moderate heating and cooling rates of 20°C·min −1 were used during the microwave annealing, which was conducted in argon gas.…”

Section: Discussionmentioning

confidence: 99%

High‐temperature strength and plastic deformation behavior of niobium diboride consolidated by spark plasma sintering

et al. 2017

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Bulk niobium diboride ceramics were consolidated by spark plasma sintering (SPS) at 1900°C. SPS resulted in dense specimens with a density of 98% of the theoretical density and a mean grain size of 6 lm. During the SPS consolidation, the hexagonal boron nitride (h-BN) was formed from B 2 O 3 on the powder particle surface and residual adsorbed nitrogen in the raw diboride powder. The roomtemperature strength of these NbB 2 bulks was 420 MPa. The flexural strength of the NbB 2 ceramics remained unchanged up to 1600°C. At 1700°C an increase in strength to 450 MPa was observed, which was accompanied by the disappearance of the secondary h-BN phase. Finally, at 1800°C signs of plastic deformation were observed. Fractographic analysis revealed a number of etching pits and steplike surfaces suggestive of high-temperature deformation. The temperature dependence of the flexural strength of NbB 2 bulks prepared by SPS was compared with data for monolithic TiB 2 , HfB 2 and ZrB 2 . Our analysis suggested that the thermal stresses accumulated during SPS consolidation may lead to additional strengthening at elevated temperatures. K E Y W O R D Shigh-temperature strength, niobium diboride, spark plasma sintering

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Section: Discussionmentioning

confidence: 99%