Thermal Corrosion Behavior and Mechanism of RE2Ti2O7 Ceramics in V2O5 and Na2SO4+V2O5 Molten Salts

doi:10.15541/jim20260081

Abstract

Abstract:

In the context of developing aircraft engines with high thrust-to-weight ratio, thermal barrier coating (TBC) materials must possess excellent thermal insulation properties and be capable of withstanding the thermal corrosion caused by molten salts (such as V₂O₅ and sulfates) in high-temperature combustion gases. In this study, RE₂Ti₂O₇ (RE=Dy and Yb) ceramics were synthesized via a solid-state sintering method. The phase stability and decomposition behavior were examined through thermogravimetric-differential scanning calorimetry (TG-DSC) analysis. The corrosion behavior of RE₂Ti₂O₇ upon exposure to V₂O₅ and Na₂SO₄+V₂O₅ molten salts at 900, 1000, and 1100 ℃ was analyzed. TG-DSC results show that RE₂Ti₂O₇ retains good thermal stability at 1100 ℃, with no obvious decomposition peaks. In a pure V₂O₅ molten salt environment, granular rare earth vanadates (REVO₄) form on the surface, accompanied by columnar TiO₂ precipitation. The corrosion products were distributed in a dense layered structure, which would limit further deep corrosion. Upon the introduction of Na₂SO₄, the NaVO₃ formed in the system reduced the local melt viscosity and significantly increased ionic mobility, thereby accelerating the dissolution and reprecipitation of rare earths and titanium. This resulted in corrosion products dominated by columnar REVO₄ and TiO₂. Based on phase diagrams and Gibbs free energy (ΔG) calculations, a reaction pathway dominated by redox reactions and ion exchange between V₂O₅ and RE₂Ti₂O₇ was proposed. Furthermore, Lewis acid-base theory was employed to explain how the addition of Na⁺ alters solvation and complexation behavior, thereby influencing the overall corrosion kinetics. In summary, RE₂Ti₂O₇ ceramics exhibit excellent corrosion resistance in high-temperature molten salts, demonstrating their potential as candidate materials for thermal barrier coatings.

Key words: thermal barrier coating, RE₂Ti₂O₇ ceramic, Na₂SO₄+V₂O₅ salt, reaction mechanism, thermal corrosion

CLC Number:

TQ174

GAO Zhixin, FU Shuai, BAO Yiwang, LÜ Kuilin, LIU Xiaogen. Thermal Corrosion Behavior and Mechanism of RE₂Ti₂O₇ Ceramics in V₂O₅ and Na₂SO₄+V₂O₅ Molten Salts[J]. Journal of Inorganic Materials, 2026, 41(10): 1533-1540.

Figures/Tables 12

Fig. 1 (a) DSC and (b) TG curves of RE2Ti2O7 samples in the temperature range of 100-1300 ℃

Fig. 2 XRD patterns of V2O5 salt and RE2Ti2O7 samples after 10 h exposure at 900, 1000, and 1100 ℃ (a) Dy2Ti2O7; (b) Yb2Ti2O7

Fig. 3 (a-c, e-g) SEM images and corresponding (d, h) elemental distributions at marked points of RE2Ti2O7+V2O5 after 10 h exposure at 900, 1000, and 1100 ℃ (a-d) Dy2Ti2O7; (e-h) Yb2Ti2O7

Fig. 4 SEM cross-sectional images of RE2Ti2O7+V2O5 after 10 h exposure at 900, 1000, and 1100 ℃ (a-c) Dy2Ti2O7; (d-f) Yb2Ti2O7

Fig. 5 XRD patterns of 50% Na2SO4 + 50% V2O5 and RE2Ti2O7 ceramics after 10 h exposure at different temperatures (a) Dy2Ti2O7; (b) Yb2Ti2O7

Fig. 6 (a-f) SEM images and elemental distributions of Dy2Ti2O7 reacting with 50% V2O5+50% Na2SO4 salt for 10 h at different temperatures; (g-l) SEM images and elemental distributions of Yb2Ti2O7 reacting with 50% V2O5+50% Na2SO4 salt for 10 h at different temperatures (a, b, g, h) 900 ℃; (c, d, i, j) 1000 ℃; (e, f, k, l) 1100 ℃

Fig. 7 SEM cross-sectional images and elemental distributions of RE2Ti2O7 and 50% Na2SO4+50% V2O5 reacted for 10 h at 900, 1000, and 1100 ℃ (a-c) Dy2Ti2O7; (d-f) Yb2Ti2O7

Fig. 8 (a) Gibbs free energy between various compounds; (b) Schematic diagram of the reaction between RE2Ti2O7 and V2O5/50% Na2SO4+50% V2O5

Fig. S1 XRD patterns of RE2Ti2O7 samples (a) Dy2Ti2O7; (b) Yb2Ti2O7

Fig. S2 Phase diagram of TiO2 and V2O5 at high temperatures[22]

Table S1 Elemental mapping of SEM image marked points showing the reaction between Dy2Ti2O7 and 50% V2O5+50% Na2SO4 salt at different temperatures in Fig. 6(b, d, f)

Temperature/℃	Point	Product	Composition/(%, in atom)
Temperature/℃	Point	Product	O	S	Na	V	Ti	Dy
900	1	Na salt	57.16±0.15	0.36±0.05	24.12±0.11	13.56±0.05	4.65±0.12	0.15±0.01
	2	DyVO₄	51.69±0.13	0.83±0.02	3.80±0.10	22.90±0.25	1.90±0.13	19.59±0.31
	3	TiO₂	57.65±0.16	0.68±0.04	8.69±0.10	1.91±0.11	30.85±0.28	0.23±0.08
1000	4	Na salt	62.02±0.12	0.32±0.06	25.63±0.19	6.39±0.13	1.16±0.02	4.48±0.11
	5	DyVO₄	59.64±0.11	/	1.70±0.02	20.71±0.14	0.79±0.06	17.15±0.12
	6	TiO₂	64.12±0.13	0.63±0.05	0.14±0.01	0.58±0.08	34.16±0.23	0.37±0.04
1100	7	Na salt	62.02±0.14	0.41±0.07	23.18±0.25	7.48±0.11	3.46±0.09	3.45±0.11
	8	DyVO₄	58.41±0.04	0.43±0.05	/	23.25±0.21	0.38±0.03	17.54±0.12
	9	TiO₂	52.49±0.05	0.20±0.01	0.29±0.01	1.99±0.03	33.45±0.25	1.16±0.04

Table S2 Elemental mapping of SEM image marked points showing the reaction between Yb2Ti2O7 and 50% V2O5+50% Na2SO4 salt at different temperatures in Fig. 6(h, j, l)

Temperature/℃	Point	Product	Composition/(%, in atom)
Temperature/℃	Point	Product	O	S	Na	V	Ti	Yb
900	10	Na salt	61.89±0.36	0.31±0.02	23.64±0.15	13.97±0.16	0.19±0.02	/
	11	YbVO₄	56.97±0.23	0.52±0.08	1.16±0.15	24.50±0.14	0.80±0.05	16.05±0.15
	12	TiO₂	63.68±0.33	0.40±0.03	2.67±0.13	3.55±0.11	28.21±0.23	1.48±0.09
1000	13	Na salt	59.42±0.35	0.89±0.07	17.24±0.14	16.05±0.22	2.23±0.09	4.17±0.14
	14	YbVO₄	50.18±0.28	0.92±0.09	2.75±0.12	21.12±0.16	2.40±0.07	19.46±0.22
	15	TiO₂	63.11±0.31	0.69±0.04	2.59±0.08	3.57±0.10	28.24±0.24	1.84±0.21
1100	16	Na salt	68.34±0.36	0.43±0.05	15.71±0.21	4.78±0.23	6.66±0.14	4.02±0.17
	17	YbVO₄	69.69±0.38	0.65±0.01	/	14.91±0.18	0.69±0.03	14.06±0.20
	18	TiO₂	66.53±0.34	0.44±0.03	2.12±0.10	1.51±0.12	25.23±0.24	1.36±0.08

References 33

[1]	GUO Y, SONG W, GUO L, et al. Molten-volcanic-ash-phobic thermal barrier coating based on biomimetic structure. Advanced Science, 2023, 10: 2205156. DOI URL
[2]	ZHOU Y, ZHOU Y, WU P, et al. Thermal properties of Y_1-_xMg_xTaO_4-_x_/2 ceramics via anion sublattice adjustment. Rare Metals, 2020, 39: 545. DOI URL
[3]	JIANG C, FENG M, YU C, et al. Thermal cycling behavior of nanostructured and conventional yttria-stabilized zirconia thermal barrier coatings via air plasma spray. Rare Metals, 2023, 42: 3859. DOI URL
[4]	FU S, JIA Z J, WAN D T, et al. Synthesis, microstructure and thermophysical properties of (La_0.2Y_0.2Sm_0.2Eu_0.2Gd_0.2)₂Zr₂O₇ high-entropy oxide ceramic. Ceramics International, 2024, 50: 5510. DOI URL
[5]	HUANG L, LIU M J, YANG G J, et al. Treelike PS-PVD coating: hierarchical branching by shading and sintering. Acta Materialia, 2024, 280: 120321. DOI URL
[6]	LI J, TONG Z, YANG Q, et al. Non-destructive evaluation of defects in thermal barrier coating system using combined electromagnetic and thermographic signals. Nature Communications, 2025, 16: 8697. DOI
[7]	HABIBI M H, GUO S M. The hot corrosion behavior of plasma sprayed zirconia coatings stabilized with yttria, ceria, and titania in sodium sulfate and vanadium oxide. Materials & Corrosion, 2015, 66: 270. DOI URL
[8]	FANG Y, CUI X, JIN G, et al. Microstructural evolution and hot corrosion behavior of La_0.8Ba_0.2TiO_3-_δYSZ double-layer thermal barrier coatings in Na₂SO₄ + V₂O₅ molten salt at 900 ℃. Surface and Coatings Technology, 2020, 399: 126175. DOI URL
[9]	GUO L, YAN Z, YU J, et al.Hot corrosion behavior of TiO₂ doped, Yb₂O₃ stabilized zirconia exposed to V₂O₅ + Na₂SO₄ molten salt at700-1000 ℃. Ceramics International, 2018, 44: 261.
[10]	SINGH Y, KUMAR V, SHARMA S K, et al. Investigations of thermal conductivity in nano-crystalline Gd₂Ti₂O₇ pyrochlore. Journal of Alloys and Compounds, 2024, 990: 174249. DOI URL
[11]	GAO Z, FU S, ZHANG L, et al. Thermodynamic characterization of RE₂Ti₂O₇ (RE = Ho, Er, Tm and Yb) ceramics as thermal barrier coating materials. Materials Today Physics, 2025, 57: 101801. DOI URL
[12]	GAO Z, FU S, ZHANG X Y, et al. Investigation of the mechanical and thermal properties of RE₂Ti₂O₇ (RE = Y, Dy, Sm) ceramics with a pyrochlore structure. Journal of the European Ceramic Society. 2025, 45: 117661. DOI URL
[13]	GAO Z, FU S, ZHANG L, et al. Study on CMAS corrosion resistance and wettability of rare-earth titanate ceramics at 1350 ℃. Applied Materials Today, 2026, 48: 103041. DOI URL
[14]	TAN Z Y, PAN T T, NIE M, et al. Exceptional hot corrosion resistance behavior and mechanism of double layered Zr₆Ta₂O₁₇/ YSZ thermal barrier coatings exposed to Na₂SO₄-V₂O₅ salt. Corrosion Science, 2025, 246: 112761. DOI URL
[15]	WANG J, WANG Y, CHEN M, et al. Degradation of CeO₂ and TiO₂ co-stabilized ZrO₂ by the V₂O₅ molten salts and Na₂SO₄ + V₂O₅ molten salts. Surface and Coatings Technology, 2022, 437: 128352. DOI URL
[16]	DONG H, REN Y, WANG D, et al. Hot corrosion behaviors of SrZrO₃ ceramic co-doped with Y₂O₃ and Yb₂O₃ in molten Na₂SO₄, V₂O₅, and Na₂SO₄+V₂O₅ salts mixture. Journal of the European Ceramic Society, 2014, 34: 3917. DOI URL
[17]	GU S, ZHANG S, JIA Y, et al. Evaluation of hot corrosion behavior of SrHfO₃ ceramic in the presence of molten sulfate and vanadate salt. Journal of Alloys and Compounds, 2017, 728: 10. DOI URL
[18]	WANG J, CHEN L, CHEN M, et al. Phase and microstructure evolution of Sc₂O₃-CeO₂-ZrO₂ ceramics in Na₂SO₄+V₂O₅ molten salts. Ceramics International, 2021, 47: 22965. DOI URL
[19]	SINGH P, PANDIT N, KESHRI A K. Plasma-sprayed GNP/CNT reinforced lanthanum-cerate coatings: hot corrosion assessment in Na₂SO₄-V₂O₅ environment. Surface and Coatings Technology, 2024, 481: 130676. DOI URL
[20]	YOKOKAWA H, SAKAI N, KAWADA T, et al. Chemical potential diagrams for rare earth-transition metal-oxygen systems: I, Ln-V-O and Ln-Mn-O System. Journal of the American Ceramic Society, 1990, 73: 649. DOI URL
[21]	LI S, LIU Z G, OUYANG J H. Growth of YbVO₄ crystals evolved from hot corrosion reactions of Yb₂Zr₂O₇ against V₂O₅ and Na₂SO₄+V₂O₅. Applied Surface Science, 2013, 276: 653. DOI URL
[22]	HABEL D, GOERKE O, TOVAR M, et al. Phase relations in the system TiO₂-V₂O_x under oxidizing and reducing conditions. Journal of Phase Equilibria and Diffusion, 2008, 29: 482. DOI URL
[23]	CAI J, WEI J, ZU Z, et al. Comparative hot corrosion performance of arc ion plated NiCoCrAlYSiHf coating in Na₂SO₄/NaCl/V₂O₅- media via high-current pulsed electron beam. Materials Characterization, 2022, 191: 112074. DOI URL
[24]	LI Z, LI X, ZHAO S, et al. Degradation of atmospheric plasma sprayed Gd₄Al₂O₉ coating attacked by molten Na₂SO₄+V₂O₅ salt mixture at 700-950 ℃. Ceramics International, 2024, 50: 12701. DOI URL
[25]	GUO L, ZHANG C, HE Q, et al. Corrosion products evolution and hot corrosion mechanisms of REPO₄ (RE= Gd, Nd, La) in the presence of V₂O₅ + Na₂SO₄ molten salt. Journal of the European Ceramic Society, 2019, 39: 1496. DOI URL
[26]	VENU D M, SREEDHAR G. Role of low-K Gd₂Ti₂O₇ addition on the oxidation and hot corrosion behavior of DySZ thermal barrier coatings. Journal of Alloys and Compounds, 2025, 1049: 185231. DOI URL
[27]	LI Y, SUN Z, HE L, et al. Thermal corrosion behavior of Yb₄Hf₃O₁₂ exposed to Na₂SO₄+V₂O₅ molten salt. Journal of Alloys and Compounds, 2024, 1008: 176501. DOI URL
[28]	YIN Q, SHEN K H, WANG Y, et al. Research progress of rare earth zirconate thermal barrier coating ceramic materials. Materials Today Communications, 2025, 42: 111579. DOI URL
[29]	SONG D, SONG T, PAIK U, et al. Hot corrosion behavior in thermal barrier coatings with heterogeneous splat boundary. Corrosion Science, 2020, 163: 108225. DOI URL
[30]	LI B, WU J, HE X, et al. Sc-doped Gd₂Zr₂O₇ coating on YSZ thermal barrier coatings to resist CMAS + molten salt attack. Ceramics International, 2022, 48: 11662. DOI URL
[31]	LANG N A. Lange’s handbook of chemistry. 16th ed. New York: McGraw-Hill Education, 2013.
[32]	KIM J, SONG D, LU G, et al. Hot corrosion behavior of Yb₂O₃-Gd₂O₃-Y₂O₃ co-stabilized zirconia-based thermal barrier coatings covered with a Lewis neutral layer. Surface and Coatings Technology, 2021, 428: 127911. DOI URL
[33]	SHAMSIPOOR A, FARVIZI M, RAZAVI M, et al. Hot corrosion behavior of thermal barrier coating on Cr₂AlC and CoNiCrAlY substrates at 950 ℃ in presence of Na₂SO₄+V₂O₅ molten salts. Surfaces and Interfaces, 2020, 21: 100679. DOI URL

Thermal Corrosion Behavior and Mechanism of RE₂Ti₂O₇ Ceramics in V₂O₅ and Na₂SO₄+V₂O₅ Molten Salts

RichHTML

PDF (PC)

Knowledge

Abstract

Cite this article

share this article

Figures/Tables 12

References 33

Related Articles 15

Recommended Articles

Metrics

Comments

[1]	XU Mingyi, XIONG Ying, WANG Bo, ZHANG Yixin, CHEN Wenbo, CAO Xueqiang. Fabrication and Properties of Magnetoplumbite-type Rare-earth Hexaaluminate Thermal Barrier Coating Materials [J]. Journal of Inorganic Materials, 2026, 41(8): 1103-1109.
[2]	WANG Junbu, HUANG Zeai, YANG Mingkai, MENG Ying, ZHOU Mingwei, ZHOU Ying. Research Progress on Anti-coking Catalytic Materials for Methane Conversion [J]. Journal of Inorganic Materials, 2026, 41(6): 739-750.
[3]	WANG Yuhe, LUO Yixiu, GUO Huiming, ZHANG Guangheng, ZHANG Siyan, SUN Luchao, WANG Jiemin, WANG Jingyang. First-principles Investigation of Elastic and Thermophysical Properties of High-entropy Rare-earth Oxide Thermal Barrier Coating Materials [J]. Journal of Inorganic Materials, 2026, 41(4): 445-454.
[4]	WU Boyu, ZHANG Shengen, ZHANG Shengyang, LIU Bo, ZHANG Bolin. Effect of CeO₂ on Low-temperature Denitrification Performance of MnO_x Catalysts and Its Mechanism [J]. Journal of Inorganic Materials, 2026, 41(1): 87-95.
[5]	LIU Jiangping, GUAN Xin, TANG Zhenjie, ZHU Wenjie, LUO Yongming. Research Progress on Catalytic Oxidation of Nitrogen-containing Volatile Organic Compounds [J]. Journal of Inorganic Materials, 2025, 40(9): 933-943.
[6]	ZHANG Ruiyang, WANG Yi, OU Bowen, ZHOU Ying. α-Ni(OH)₂ Surface Hydroxyls Synergize Ni³⁺ Sites for Catalytic Formaldehyde Oxidation [J]. Journal of Inorganic Materials, 2023, 38(10): 1216-1222.
[7]	AN Wenran, HUANG Jingqi, LU Xiangrong, JIANG Jianing, DENG Longhui, CAO Xueqiang. Effect of Heat-treatment Temperature on Thermal and Mechanical Properties of LaMgAl₁₁O₁₉ Coating [J]. Journal of Inorganic Materials, 2022, 37(9): 925-932.
[8]	WEI Hailang, CAO Xueqiang, DENG Longhui, JIANG Jianing. Thermodynamic Properties and Thermal Cycling Lifetimes of LaMeAl₁₁O₁₉/YSZ Thermal Barrier Coatings [J]. Journal of Inorganic Materials, 2022, 37(12): 1259-1266.
[9]	GAO Wa, XIONG Yujie, WU Congping, ZHOU Yong, ZOU Zhigang. Recent Progress on Photocatalytic CO₂ Reduction with Ultrathin Nanostructures [J]. Journal of Inorganic Materials, 2022, 37(1): 3-14.
[10]	ZHENG Yanning, JI Junrong, LIANG Xueling, LAI Zhengjie, CHENG Qifan, LIAO Dankui. Performance of Nitrogen-doped Hollow Carbon Spheres as Oxidase Mimic [J]. Journal of Inorganic Materials, 2021, 36(5): 527-534.
[11]	ZHU Jiatong, LOU Zhihao, ZHANG Ping, ZHAO Jia, MENG Xuanyu, XU Jie, GAO Feng. Preparation and Thermal Properties of Rare Earth Tantalates (RETaO₄) High-Entropy Ceramics [J]. Journal of Inorganic Materials, 2021, 36(4): 411-417.
[12]	JI Xiaojuan,YU Yueguang,LU Xiaoliang. Effects of Impurities on Properties of YSZ Thermal Barrier Coatings [J]. Journal of Inorganic Materials, 2020, 35(6): 669-674.
[13]	XU Yun-Qing,WANG Hai-Zeng. Sodium Magnesium Fluoride Particles of Different Morphologies: Prepared by EDTA-assisted Hydrothermal Method [J]. Journal of Inorganic Materials, 2019, 34(9): 933-937.
[14]	Bo-Le MA, Wen MA, Wei HUANG, Yu BAI, Rui-Ling JIA, Hong-Ying DONG. Thermophysical Property of Single-phase Strontium Zirconate Co-doped with Double Rare-earth Oxides as a Thermal Barrier Coating Material [J]. Journal of Inorganic Materials, 2019, 34(4): 394-400.
[15]	WANG Lin, DING Kun-Ying, LIN Xiao-Ping, LI Ze, ZHENG Run-Guo, YANG Lian-Wei. Defect Evolution and Microcracks of 8YSZ Double-layer Thermal Barrier Coatings by Water Immersion Ultrasound Macroscopic Detection [J]. Journal of Inorganic Materials, 2019, 34(12): 1265-1271.