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Ablation behavior of ZrB2-SiC-LaB6 ultra-high temperature ceramics prepared by ultrafine multiphase powders combined with spark plasma sintering.

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Title:	Ablation behavior of ZrB2-SiC-LaB6 ultra-high temperature ceramics prepared by ultrafine multiphase powders combined with spark plasma sintering.
Authors:	Zhou, Zhe¹ (AUTHOR) zhouzhe0810@csust.edu.cn, Xia, Dawang^1,2 (AUTHOR), Wang, Jie¹ (AUTHOR), Guo, Zheng¹ (AUTHOR), Liu, Kuihong¹ (AUTHOR), Li, Taiyu¹ (AUTHOR), Li, Zhi² (AUTHOR), Liu, Danxia¹ (AUTHOR)
Source:	Ceramics International. May2026:Part B, Vol. 52 Issue 12, p19958-19970. 13p.
Subjects:	Ultra-high-temperature ceramics, Zirconium boride, Sintering, Oxide coating, Silicon carbide, Mechanical behavior of materials
Abstract:	ZrB 2 -SiC-LaB 6 UHTCs were prepared using ultrafine multiphase powders synthesized by sol-gel method and borocarbon thermal reduction, combined with the SPS sintering technique. The mechanism of densification and ablation resistance were studied. The UHTCs consist of a ZrB 2 grain skeleton and a nano-mixed phase of SiC, LaB 6 , La 6 (Si 4 O 13)(SiO 4) 2. As the sintering temperature increases from 1700 °C to 2000 °C, the nano-mixed phase grows and the La 6 (Si 4 O 13)(SiO 4) 2 phase transforms into SiC and LaB 6 phases, leaving a small amount of intracrystalline pores. The hardness of the ceramics prepared by this process increased from 417HV 10 to 1024HV 10 , and the relative density increased from 82.36% to 93.86%. After oxyacetylene ablation at 1900 °C for 120 s, the surface of the ceramic oxide layer was flat without flaking and cracking. Among them, the UHTC sintered at 1800 °C has the best ablation resistance, with a mass ablation rate of 0.57 mg/s and a line ablation rate of 1.25 μm/s. During the ablation process, La 2 O 3 reacted with ZrO 2 and SiO 2 on the oxide surface through liquid-phase mass transfer to generate high-viscosity La 4.67 (SiO 4) 3 O and La 2 Zr 2 O 7 , and formed a four-layer oxide structure to protect the substrate. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	ZrB 2 -SiC-LaB 6 UHTCs were prepared using ultrafine multiphase powders synthesized by sol-gel method and borocarbon thermal reduction, combined with the SPS sintering technique. The mechanism of densification and ablation resistance were studied. The UHTCs consist of a ZrB 2 grain skeleton and a nano-mixed phase of SiC, LaB 6 , La 6 (Si 4 O 13)(SiO 4) 2. As the sintering temperature increases from 1700 °C to 2000 °C, the nano-mixed phase grows and the La 6 (Si 4 O 13)(SiO 4) 2 phase transforms into SiC and LaB 6 phases, leaving a small amount of intracrystalline pores. The hardness of the ceramics prepared by this process increased from 417HV 10 to 1024HV 10 , and the relative density increased from 82.36% to 93.86%. After oxyacetylene ablation at 1900 °C for 120 s, the surface of the ceramic oxide layer was flat without flaking and cracking. Among them, the UHTC sintered at 1800 °C has the best ablation resistance, with a mass ablation rate of 0.57 mg/s and a line ablation rate of 1.25 μm/s. During the ablation process, La 2 O 3 reacted with ZrO 2 and SiO 2 on the oxide surface through liquid-phase mass transfer to generate high-viscosity La 4.67 (SiO 4) 3 O and La 2 Zr 2 O 7 , and formed a four-layer oxide structure to protect the substrate. [ABSTRACT FROM AUTHOR]
ISSN:	02728842
DOI:	10.1016/j.ceramint.2026.03.086