Ablation Resistance of High-entropy Oxide Coatings on C/C Composites

doi:10.15541/jim20230370

Abstract

Abstract:

With improvement in service temperature of thermal structural components for the new generation hypersonic aircraft, higher requirements are put forward for the phase stability and ablation resistance of the thermal protection coatings (TPCs). Carrying out high-entropy design for traditional transition metal oxide ZrO₂ and HfO₂ coatings, solid-phase reaction and supersonic atmosphere plasma spraying (SAPS) were applied to prepare (Hf_0.125Zr_0.125Sm_0.25Er_0.25Y_0.25)O_2-_δ (M1R3O), (Hf_0.2Zr_0.2Sm_0.2Er_0.2Y_0.2)O_2-_δ (M2R3O), (Hf_0.25Zr_0.25Sm_0.167Er_0.167Y_0.167)O_2-_δ (M3R3O) high-entropy oxide (HEO) coatings. The effects of rare earth content on phase structure evolution, phase stability and ablative resistance of HEO coatings were investigated. M2R3O coating and M3R3O coating possessed excellent phase stability and ablation resistance, which maintained stable phase structure after ablation by oxygen-acetylene flame with heat flux density of 2.38-2.40 MW/m², without decomposition of solid solution and precipitation of rare earth components. Mass ablation rate and linear ablation rate of M2R3O coating after cyclic ablation for 180 s are 0.01 mg/s and -1.16 μm/s, respectively. Compared with M1R3O coating (0.09 mg/s, -1.34 μm/s) and M3R3O coating (0.02 mg/s, -4.51 μm/s), the reductions of ablation rate are 88.9%, 13.4%, respectively, and 50.0%, 74.3% for M2R3O coatings, respectively, presenting the best ablation resistance. M2R3O coating exhibits excellent ablation resistance due to its high melting point (>2200 ℃) and low thermal conductivity ((1.07±0.09) W/(m·K)), which effectively protects the internal SiC transition layer and C/C composites from oxidation damage, avoiding interface cracking caused by the formation of SiO₂ phase.

Key words: high-entropy ceramic, transition metal oxide, thermal spray, thermal protection coating, ablation resistance, C/C composite

CLC Number:

TB332

GUO Lingxiang, TANG Ying, HUANG Shiwei, XIAO Bolan, XIA Donghao, SUN Jia. Ablation Resistance of High-entropy Oxide Coatings on C/C Composites[J]. Journal of Inorganic Materials, 2024, 39(1): 61-70.

Figures/Tables 19

Table 1 Compositions and component molar ratios of high-entropy oxides in this study

Label	Constituent	$\frac{n(\text{Hf}+\text{Zr})}{n(\text{Sm}+\text{Er}+\text{Y})}$
M1R3O	(Hf_0.125Zr_0.125Sm_0.25Er_0.25Y_0.25)O_2-_δ	1/3
M2R3O	(Hf_0.2Zr_0.2Sm_0.2Er_0.2Y_0.2)O_2-_δ	2/3
M3R3O	(Hf_0.25Zr_0.25Sm_0.167Er_0.167Y_0.167)O_2-_δ	3/3

Table 2 Parameters of SAPS for high-entropy oxide coatings

Parameter	Value
Current/A	410-430
Voltage/V	100-120
Primary gas Ar/(L·min^-1)	65-70
Second gas H₂/(L·min^-1)	3.5-5.0
Powder flow Ar/(L·min^-1)	5-7
Spray distance/mm	100
Powder feed rate/(g·min^-1)	5-6

Fig. 1 Phase characterizations of high-entropy oxide powders (a) XRD pattern of M2R3O and standard diffraction peaks for each single-component oxide; (b) XRD patterns of three high-entropy oxides; (c) Ideal crystal structure; (d) Raman spectra of three high-entropy oxides

Fig. 2 TEM analyses of M2R3O powders (a) Morphology; (b) High-resolution TEM (HRTEM) image; (c) Selective area electron diffraction (SAED) pattern; (d) High-angle annular dark field (HAADF) image and corresponding element mappings

Fig. 3 Surface and cross-section morphologies of high-entropy oxide coatings (a, d) M1R3O coating; (b, e) M2R3O coating; (c, f) M3R3O coating

Fig. 4 XRD patterns of high-entropy oxide coatings (a) Full spectrum diffraction; (b) M1R3O coating and refinement pattern; (c) M2R3O coating and refinement pattern; (d) M3R3O coating and refinement pattern

Fig. 5 Binary phase diagrams of HfO2-RE2O3 and ZrO2-RE2O3 (RE=Sm, Er and Y)[30] (a) HfO2-Sm2O3; (b) HfO2-Er2O3; (c) HfO2-Y2O3; (d) ZrO2-Sm2O3; (e) ZrO2-Er2O3; (f) ZrO2-Y2O3

Fig. 6 Surface temperature curves of high-entropy oxide coatings during ablation

Fig. 7 Macro morphologies of high-entropy oxide coatings after ablation

Fig. 8 Mass ablation ratios and line ablation ratios of high- entropy oxide coatings

Fig. 9 XRD patterns of high-entropy oxide coatings after ablation (a) M1R3O; (b) M2R3O; (c) M3R3O

Fig. 10 Cross-section morphologies and EDS analyses of high-entropy oxide coatings after cyclic ablation for 180 s(a-c) M1R3O; (d-f) M2R3O; (g-i) M3R3O

Fig. 11 Comparison of ablation resistances between high-entropy oxide coatings and other coatings in the same ablation environment

Fig. S1 TEM analysis of M1R3O powders (a) Morphology; (b) HRTEM image; (c) SAED pattern; (d) HAADF image and its corresponding element mappings

Fig. S2 TEM analysis of M3R3O powders (a) Morphology; (b) HRTEM image; (c) SAED pattern; (d) HAADF image and its corresponding element mappings

Fig. S3 XRD refinement patterns of high-entropy oxide powders (a) M1R3O; (b) M2R3O; (c)M3R3O

Fig. S4 Thermal conductivities of high-entropy oxides

Fig. S5 Surface microstructures of high-entropy oxide coatings after ablation (a-c) M2R3O coatings; (d-f) M3R3O coatings

Tabel S1 EDS element point scanning analysis

	Hf	Zr	Sm	Er	Y	Si	O
Spot A/(%, in atom)	10.5	5.6	9.3	8.5	8.4	—	57.7
Spot B/(%, in atom)	5.6	4.7	5.1	8.7	10.4	3.8	61.7

References 43

[1]	NI D, CHENG Y, ZHANG J, et al. Advances in ultra-high temperature ceramics, composites, and coatings. Journal of Advanced Ceramics, 2022, 11(1):1. DOI
[2]	DU H. Research progress on integrated thermal management and key technology of hypersonic vehicles. Equipment Environmental Engineering, 2023, 20(1):43.
[3]	REGHU V R, SHANKAR V, RAMASWAMY P. Challenges in plasma spraying of 8%Y₂O₃-ZrO₂ thermal barrier coatings on Al alloy automotive piston and influence of vibration and thermal fatigue on coating characteristics. Materials Today: Proceedings, 2018, 5(11):23927. DOI URL
[4]	WANG J, LU X, HU M, et al. Phase stability, thermophysical properties, thermal shock behavior and CMAS resistance of Sc₂O₃-CeO₂ co-stabilized ZrO₂ TBCs. Surface and Coatings Technology, 2023, 467: 129679.
[5]	LI C, FAN H, NI L, et al. Phase transformation and thermal conductivity of the APS Y₂O₃ doped HfO₂ coating with hybrid structure. Ceramics International, 2022, 48(14):19633. DOI URL
[6]	WU Y, HONG D, ZHONG X, et al. Research progress on hafnium-based thermal barrier coatings materials. Ceramics International, 2023, 49(13):21133. DOI URL
[7]	WU H, DUAN Y, LIU K, et al. First-principles study of phase transition and band structure of ZrO₂ under pressure. Journal of Alloys and Compounds, 2015, 645: 352.
[8]	MANDAL G, JANA R, SAHA P, et al. Study of structural phase transition of HfO₂ at high pressure. Materials Today: Proceedings, 2016, 3(9):2997. DOI URL
[9]	PAN L, HE L, NIU Z, et al. Corrosion behavior of ytterbium hafnate exposed to water-vapor with Al(OH)₃ impurities. Journal of the European Ceramic Society, 2023, 43(2):612. DOI URL
[10]	HE L, PAN L, ZHOU W, et al. Thermal corrosion behavior of Yb₄Hf₃O₁₂ ceramics exposed to calcium-ferrum-alumina-silicate (CFAS) at 1400 ℃. Journal of the European Ceramic Society, 2023, 43(9):4114. DOI URL
[11]	LIU X Y, CHE J W, YI H, et al. Influence of powder states on the composition and phase stability of LZ/YSZ composite thermal barrier coatings. Ceramics International, 2018, 44(16):20291. DOI URL
[12]	LIU D, WEN T, YE B, et al. Synthesis of superfine high-entropy metal diboride powders. Scripta Materialia, 2019, 167: 110.
[13]	YE B, WEN T, NGUYEN M C, et al. First-principles study, fabrication and characterization of (Zr_0.25Nb_0.25Ti_0.25V_0.25)C high- entropy ceramics. Acta Materialia, 2019, 170: 15.
[14]	SUN L, REN X, DU T, et al. High entropy engineering: new strategy for the critical property optimizations of rare earth silicates. Journal of Inorganic Materials, 2020, 36(4):339. DOI URL
[15]	SUN Y, YE L, ZHAO W, et al. Synthesis of high entropy carbide nano powders via liquid polymer precursor route. Journal of Inorganic Materials, 2021, 36(4):393. DOI URL
[16]	ANAND G, WYNN A P, HANDLEY C M, et al. Phase stability and distortion in high-entropy oxides. Acta Materialia, 2018, 146: 119.
[17]	PIANASSOLA M, ANDERSON K L, SAFIN J, et al. Tuning the melting point and phase stability of rare-earth oxides to facilitate their crystal growth from the melt. Journal of Advanced Ceramics, 2022, 11(9):1479. DOI
[18]	SUN J, GUO L, ZHANG Y, et al. Superior phase stability of high entropy oxide ceramic in a wide temperature range. Journal of the European Ceramic Society, 2022, 42(12):5053. DOI URL
[19]	LI Y, LIU Y, GUO C, et al. Ablation resistance of ZrC-based composite coating with multi-layer structure for carbon/carbon composites above 2200 ℃. Corrosion Science, 2022, 207: 110600.
[20]	GUO X, ZHANG Y, LI T, et al. High-entropy rare-earth disilicate (Lu_0.2Yb_0.2Er_0.2Tm_0.2Sc_0.2)₂Si₂O₇: a potential environmental barrier coating material. Journal of the European Ceramic Society, 2022, 42(8):3570. DOI URL
[21]	WANG J, WU F, ZOU R, et al. High-entropy ferroelastic rare-earth tantalite ceramic: (Y_0.2Ce_0.2Sm_0.2Gd_0.2Dy_0.2)TaO₄. Journal of the American Ceramic Society, 2021, 104(11):5873. DOI URL
[22]	ZHANG F, GUO M, MIAO Y, et al. Preparation and sintering behavior of high entropy ceramic (Zr_1/7Hf_1/7Ce_1/7Y_2/7La_2/7)O_2-_δ. Journal of Inorganic Materials, 2021, 36(4):372. DOI URL
[23]	ZHAO Z, CHEN H, XIANG H, et al.(Y_0.25Yb_0.25Er_0.25Lu_0.25)₂ (Zr_0.5Hf_0.5) ₂O₇: a defective fluorite structured high entropy ceramic with low thermal conductivity and close thermal expansion coefficient to Al₂O₃. Journal of Materials Science & Technology, 2020, 39: 167.
[24]	GILD J, SAMIEE M, BRAUN J L, et al. High-entropy fluorite oxides. Journal of the European Ceramic Society, 2018, 38(10):3578. DOI URL
[25]	WRIGHT A J, WANG Q, HU C, et al. Single-phase duodenary high-entropy fluorite/pyrochlore oxides with an order-disorder transition. Acta Materialia, 2021, 211: 116858.
[26]	ZHOU L, LI F, LIU J, et al. High-entropy thermal barrier coating of rare-earth zirconate: a case study on (La_0.2Nd_0.2Sm_0.2Eu_0.2Gd_0.2)₂Zr₂O₇ prepared by atmospheric plasma spraying. Journal of the European Ceramic Society, 2020, 40(15):5731. DOI URL
[27]	DA COSTA PINTO C, CHAUDHURI P, GHOSH A, et al. Mechanical alloying synthesis of Sm₃NbO₇ defect fluorite and structural characterization by X-ray diffraction, Raman spectroscopy and DFT calculation. Ceramics International, 2021, 47(7):8936. DOI URL
[28]	FENG G, YAO X, YU Y, et al. Synthesis and performance characterization of Hafnium-based multilayer coating applied over carbon/carbon composites with sharp leading edge. Journal of Materials Science & Technology, 2023, 153: 254.
[29]	HU D, ZHANG Y, DONG Z, et al. Relationship analyses on environmental factors-ablation performance based on ZrC-TaC system: oxygen partial pressure and gas flow scouring. Journal of the European Ceramic Society, 2023, 43(6):2331. DOI URL
[30]	ANDRIEVSKAYA E R. Phase equilibria in the refractory oxide systems of zirconia, hafnia and yttria with rare-earth oxides. Journal of the European Ceramic Society, 2008, 28(12):2363. DOI URL
[31]	ANANDKUMAR M, TROFIMOV E. Synthesis, properties, and applications of high-entropy oxide ceramics: current progress and future perspectives. Journal of Alloys and Compounds, 2023, 960: 170690.
[32]	HU D, FU Q, TONG M, et al. Multiple cyclic ablation behaviors of multilayer ZrC-TaC coating with ZrC-SiC interface layer. Corrosion Science, 2022, 200: 110215.
[33]	ZE Y, WANG D, XIONG X, et al. Ablation-resistant carbide Zr_0.8Ti_0.2C_0.74B_0.26 for oxidizing environments up to 3000 ℃. Nature Communications, 2017, 8: 15836.
[34]	GU S, ZHANG S, LIU F, et al. New anti-ablation candidate for carbon/carbon composites: preparation, composition and ablation behavior of Y₂Hf₂O₇ coating under an oxyacetylene torch. Journal of the European Ceramic Society, 2018, 38(15):5082. DOI URL
[35]	YU Y, FENG G, JIA Y, et al. Nanosized (Zr, Hf)O₂ coating reinforced by AlN whiskers for the ablation protection of SiC coated C/C composites. Journal of the European Ceramic Society, 2023, 43(9):3959. DOI URL
[36]	FENG G, LI H, YAO X, et al. Investigation on the relationship between multilayer architecture and ablation behavior using an oxyacetylene torch. Corrosion Science, 2022, 198: 110104.
[37]	ZHANG J, ZHANG Y, ZHANG T, et al. Cyclic ablation behavior and microstructure evolution of multi-layer coating on C/C composites under oxyacetylene torch. Ceramics International, 2022, 48(15):21709. DOI URL
[38]	FENG G, LI H, YAO X, et al. Ablation resistance of HfC- TaC/HfC-SiC alternate coating for SiC-coated carbon/carbon composites under cyclic ablation. Journal of the European Ceramic Society, 2021, 41(6):3207. DOI URL
[39]	REN J, ZHANG Y, ZHANG P, et al. Ablation resistance of HfC coating reinforced by HfC nanowires in cyclic ablation environment. Journal of the European Ceramic Society, 2017, 37(8):2759. DOI URL
[40]	LI J, ZHANG Y, WANG H, et al. Long-life ablation resistance ZrB₂-SiC-TiSi₂ ceramic coating for SiC coated C/C composites under oxidizing environments up to 2200 K. Journal of Alloys and Compounds, 2020, 824: 153934.
[41]	ZHANG Y, SUN J, GUO L, et al. Ablation behavior under oxyacetylene torch of ZrC coating modified by SiC/TaC nanocomposites. Corrosion Science, 2022, 205: 110423.
[42]	ZHANG Y, HU H, ZHANG P, et al. SiC/ZrB₂-SiC-ZrC multilayer coating for carbon/carbon composites against ablation. Surface and Coatings Technology, 2016, 300: 1.
[43]	FENG G, CHEN L, YAO X, et al. Design and characterization of zirconium-based multilayer coating for carbon/carbon composites against oxyacetylene ablation. Corrosion Science, 2021, 192: 109785.