Oxidation behaviour of SiC coated C/C–ZrC–ZrB 2 –SiC composites in wind tunnel at 1600°C

In this research, the high-duration ablation resistance of SiC-gradient coating was investigated. SiC coating was prepared on graphite by reactive melt infiltration method at 1873 K under the argon atmosphere. Formation of the SiC layer with gradient distribution of Si and C elements was confirmed by X-ray diffraction patterns and scanning electron microscope micrographs. The results of the ablation test showed that SiC-graded coating with a proper adhesion could protect the graphite substrate up to 2073 K. The mass ablation rate for the SiC-graded coating after the 60 and 360 s ablation test under supersonic flame were −0.346 × 10 −3 g/ cm 2 s and −0.022 × 10 −3 g/cm 2 s, respectively. The results indicated that the ablation mechanism of the SiC coating under supersonic flame is the SiO 2 scouring from the central ablation region to the outer ablation region in the layer by layer form.

Section: Introductionmentioning

confidence: 99%

High duration ablation resistance of C/SiC functionally gradient coating under supersonic flame

Torabi

Valefi

Ehsani

2020

“…Among Ceramic materials, SiC has suitable properties such as low-density, physical-chemical compatibility and wettability with graphite [13]. Moreover, in oxidising environments, the formation of a self-healing glassy SiO 2 layer on the surface provides carbon materials with oxidation resistance by preventing oxygen inward diffusion [14]. To reduce the effect of coefficient of thermal expansion (CTE) mismatch between SiC and graphite, a functionally graded coating (FGC) should be applied on graphite.…”

Section: Introductionmentioning

confidence: 99%

Ablation behaviour of ZrC coating by novel solid shielding/shrouded plasma spray

Eshaghi

Valefi

Ehsani

2021

In this study, for the first time, ZrC coating was deposited on SiC coated graphite by optimized atmospheric plasma spray (i.e. solid shielding shrouded plasma spray (SSPS)) method. Then SSPS-ZrC coatings were compared with the atmospheric plasma spray APS-ZrC coatings. The results indicated that the the SSPS-ZrC coated sample had lower porosity compared with APS-ZrC coating (3% and 7.5% respectively) and the ablation test revealed that the linear and mass ablation rates of the ZrC coating applied by APS method were 3.7×10 −3 mm.s −1 and 22×10 −3 g.s −1 , while those for SSPS coating were 2.2×10 −3 mm.s −1 and 14×10 −3 g.s −1 , respectively. The results showed that applying the ZrC coating with the SSPS method can improve the ablation resistance of the equipment used in harsh conditions, significantly. It is attributed to the formation of a continuous zirconia (ZrO 2 ) layer on the surface during the ablation test of the ZrC coating.

“…β-SiC interlayer is currently prepared by chemical vapour deposition (CVD) using deposition temperatures in the range of 1000°C [14][15][16][17]. The high temperature during CVD causes changes in stress states between the binding phase and hard phase as well as to the microstructure of the substrate, which leads to a deterioration of mechanical properties of substrate and performance degradation of cemented carbide tools.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature β-SiC interlayer for diamond film on cemented carbide

Ren

Liu

et al. 2019

The adhesion of protective diamond films to cemented carbide substrates used in fabrication of space drilling tools can be improved by the inclusion of β-SiC interlayers. Conventional CVD methods for depositing the SiC interlayers lead to interface coarsening and heat stress resulting from high temperatures of deposition. In this work, a mid-frequency magnetron sputtering technique is used to deposit the β-SiC interlayer at lower temperatures, and the effects of deposition temperature on the microstructure and properties of the interlayer and final diamond film are assessed. The results show that the β-SiC interlayers deposited at temperatures exceeding 300°C possess high compactness and crystallinity. Increasing crystal β-SiC phase has beneficial effects on the nucleation and growth of diamond film. Based on the experimental data, a six-step reaction model is proposed to show the mechanism by which the β-SiC interlayer promotes the nucleation and growth of diamond films.