中子辐照6H-SiC热力学及辐照缺陷高温回复动力学

doi:10.15541/jim20250216

摘要/Abstract

摘要： 碳化硅(SiC)是核反应堆结构材料的重要候选材料,其辐照损伤行为与高温回复机制直接影响材料的服役性能与寿命。为阐明中子辐照对掺氮(N_D ≈ 3.0×10¹⁹ cm^-3)6H-SiC性能的影响及缺陷高温回复机制,本研究系统探究了中子辐照(辐照温度~150℃,剂量2.58×10²⁰ n/cm²)和等时退火过程中的缺陷演化与热力学行为。结合不同表征技术和第一性原理计算,深入解析了材料结构与性能演变。主要结果如下：(1) 辐照引发晶格显著肿胀(a、c轴及晶胞体积V肿胀率分别为0.416%、0.430%和1.310%),晶体保持单晶结构;(2) 辐照使比热增加14.7%,并在100~500 ℃温升过程中释放375.4 J/g辐照储能;(3) 基于晶胞参数回复与拉曼光谱演化,揭示了缺陷高温回复的四阶段动力学：室温至600 ℃阶段以C-Frenkel近距复合主导,迁移能E_a ≈ 0.14 eV;600~850 ℃阶段涉及Si-Frenkel复合及碳间隙原子迁移,E_a ≈ 0.26 eV;850~1200 ℃阶段为空位迁移驱动的晶格重构,E_a ≈ 0.65 eV;1200~1500 ℃阶段为碳空位(V_C)长程扩散及N_CV_Si复合体的解离,E_a ≈ 1.5 eV);(4) 拉曼与荧光光谱结果确认氮掺杂形成N_CV_Si缺陷构型,在785 nm激发下产生826 nm特征发光峰(对应634 cm⁻¹拉曼频移)。本研究揭示了中子辐照6H-SiC的缺陷回复路径与迁移能,阐明其热力学响应与高温回复动力学机制,为核用SiC材料的辐照损伤评估、性能预测及退火工艺优化提供了重要依据。

关键词: 辐照储能, 比热, 拉曼光谱, 缺陷发光, 阿伦尼乌斯

Abstract: Silicon carbide (SiC) is a promising material for nuclear reactor structures due to its excellent radiation resistance and high-temperature performance. The behavior of irradiation damage and the mechanisms of high-temperature recovery in SiC directly affect its service performance and longevity in nuclear environments. This study systematically investigated the effects of neutron irradiation on the properties of 6H-SiC, with a particular focus on the high-temperature recovery mechanisms of irradiation-induced defects. Specifically, defect evolution and thermodynamic responses in nitrogen-doped (N_D ≈ 3.0×10¹⁹ cm⁻³) 6H-SiC subjected to neutron irradiation (irradiation temperature~150 ℃, fluence 2.58×10²⁰ n/cm²) followed by isochronal annealing were examined. Integrated techniques and first-principles calculations were employed to comprehensively analyze structural and property evolution. The key findings of our study were as follows: (1) Significant lattice swelling was observed during irradiation, with swelling rates of 0.416% along the a-axis, 0.430% along the c-axis, and a 1.310% increase in the unit cell volume, all while maintaining the integrity of single-crystalline structure. (2) A 14.7% increase in specific heat capacity was recorded, with 375.4 J/g of stored irradiation energy being released during heating from 100 ℃ to 500 ℃. (3) a four-stage defect recovery kinetic model was proposed based on the recovery of lattice parameters and the evolution of Raman spectra: Stage I (RT-600 ℃): This stage is primarily dominated by the close-range recombination of carbon Frenkel pairs, with a migration energy (E_a) of approximately 0.14 eV. Stage II (600-850 ℃): This stage involves the recombination of silicon Frenkel pairs and the migration of carbon interstitials (E_a ≈ 0.26 eV). Stage III (850-1200 ℃): Lattice reconstruction driven by vacancy migration occurs, with a migration energy of approximately 0.65 eV. Stage IV (1200-1500 ℃): This stage is characterized by long-range diffusion of carbon vacancies (V_C) and the dissociation of N_CV_Si complexes, with a migration energy of approximately 1.5 eV. (4) Raman and photoluminescence spectroscopy confirms the presence of nitrogen-stabilized N_CV_Si defect configurations, which exhibit a characteristic emission peak at 826 nm (634 cm⁻¹ Raman shift) when excited with 785 nm light. This study quantitatively reveals the defect recovery pathways and migration energies in neutron-irradiated 6H-SiC, thereby enhancing understanding of its thermodynamic responses and high-temperature recovery kinetics. It provides a critical foundation for evaluating radiation damage, predicting performance, and optimizing annealing processes in nuclear-grade SiC materials.

Key words: irradiation-induced energy storage, specific heat, Raman spectroscopy, defect luminescence, Arrhenius

中图分类号:

朱飞, 郝旭洁, 张全贵, 闫新越, 刘洪飞, 张博, 李欣, 刘德峰, 妥雅勇, 张守超. 中子辐照6H-SiC热力学及辐照缺陷高温回复动力学[J]. 无机材料学报, DOI: 10.15541/jim20250216.

ZHU Fei, HAO Xujie, ZHANG Quangui, YAN Xinyue, LIU Hongfei, ZHANG Bo, LI Xin, LIU Defeng, TUO Yayong, ZHANG Shouchao. Thermodynamic and High-temperature Recovery Kinetics of Irradiation Defects in Neutron-irradiated 6H-SiC[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20250216.

参考文献

[1] HU L Y, TURNER J, BUCKLEY J,et al. A review on properties required for FB-CVD fabricated SiC for TRISO fuel production. Progress in Nuclear Energy, 2025, 185: 105762.
[2] CAPAN I.Electrically active defects in 3C, 4H, and 6H silicon carbide polytypes: a review.Crystals, 2025, 15(3): 255.
[3] WU R X, CHEN H, ZHOU Y C,et al. Advances in silicon carbides and their EMS pressure sensors for high temperature and pressure applications. ACS Applied Materials & Interfaces, 2025, 17(18): 26117.
[4] GUERNOUB S, TOUATI I, KHOUALDIA A,et al. Quantification of the impact of hexagonal percentage on the elastic and acoustic properties of SiC polytypes (3C, 10H, 8H, 6H and 4H). Silicon, 2025, DOI: 10.1007/s12633-025-03326-3.
[5] LAI L L, CUI Y X, ZHONG Y,et al. Impacts of silicon carbide defects on electrical characteristics of SiC devices. Journal of Applied Physics, 2025, 137(6): 060701.
[6] ZHANG J T, WU Z Z, HUANG J,et al. Damage behavior of He-irradiated sintered SiC at high temperatures. Journal of Nuclear Materials, 2025, 612: 155839.
[7] HIRST C A, GRANBERG F, KOMBAIAH B,,et al. Revealing hidden defects through stored energy measurements of radiation damage. Science Advances. Revealing hidden defects through stored energy measurements of radiation damage. Science Advances, 2022, 8(31): eabn2733.
[8] CAI Z Q, YUAN X W, XU C,et al. Grain boundary effects on chemical disorders and amorphization-induced swelling in 3C-SiC under high-temperature irradiation: from atomic simulation insight. Journal of the European Ceramic Society, 2024, 44(12): 6911.
[9] GUO D X, GONG H F, CHEN M Z,et al. Computational framework for thermal conductivity and volumetric swelling of irradiated silicon carbide. Nuclear Engineering and Design, 2025, 438: 114073.
[10] SNEAD L L, KATOH Y, KOYANAGI T,et al. Stored energy release in neutron irradiated silicon carbide. Journal of Nuclear Materials, 2019, 514: 181.
[11] SPROUSTER D J, KOYANAGI T, DREY D L,et al. Atomic and microstructural origins of stored energy release in neutron-irradiated silicon carbide. Physical Review Materials, 2021, 5(10): 103601.
[12] KOYANAGI T, WANG H, KARAKOC O,et al. Mechanisms of stored energy release in silicon carbide materials neutron-irradiated at elevated temperatures. Materials & Design, 2022, 214: 110413.
[13] WANG J C, KONG B, ZENG T,et al. Hybrid functional study on the intrinsic defect, extrinsic n-and p-type doping in 6H-SiC. The Journal of Physical Chemistry C, 2025, 129(14): 7000.
[14] CAPITANI G C, DI PIERRO S, TEMPESTA G.The 6H-SiC structure model: further refinement from SCXRD data from a terrestrial moissanite.American Mineralogist, 2007, 92(2-3): 403.
[15] WANG H, YAN Z F, ZHENG J,et al. Ab initio study of neutral point defect properties in 6H-SiC based on the SCAN functional. Journal of Nuclear Materials, 2025, 605: 155582.
[16] LIAO W L, HE C H, HE H.Molecular dynamics simulation of displacement damage in 6H-SiC.Radiation Effects and Defects in Solids, 2019, 174(9-10): 729.
[17] MATTAUSCH A, BOCKSTEDTE M, PANKRATOV O.Structure and vibrational spectra of carbon clusters in SiC.Physical Review B, 2004, 70(23): 235211.
[18] IDRIS M I, YAMAZAKI S, YOSHIDA K,et al. Recovery behavior of high purity cubic SiC polycrystals by post-irradiation annealing up to 1673 K after low temperature neutron irradiation. Journal of Nuclear Materials, 2015, 465: 814.
[19] ZHANG S C, CHEN H Y, LIU H F,et al. High temperature recovery of neutron irradiation-induced swelling and optical property of 6H-SiC. Journal of Inorganic Materials, 2023, 38(6): 678.
[20] CAMPBELL A A, PORTER, W D, KATOH, Y,et al. Method for analyzing passive silicon carbide thermometry with a continuous dilatometer to determine irradiation temperature. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2016, 370: 49.
[21] XI J Q, LIU C, SZLUFARSKA I.Effects of point defects on oxidation of 3C-SiC.Journal of Nuclear Materials, 2020, 538: 152308.
[22] XIE Q, LIU X, ZHOU S G,et al. Temperature-dependent oxidation behavior of silicon carbide surface: reactive molecular dynamics simulations. ACS Applied Materials & Interfaces, 2024, 16(41): 56376.
[23] JACOBSON N S, MYERS D L.Active oxidation of SiC.Oxidation of Metals, 2011, 75: 1.
[24] KATOH Y, SNEAD L L, SZLUFARSKA I,et al. Radiation effects in SiC for nuclear structural applications. Current Opinion in Solid State and Materials Science, 2012, 16(3): 143.
[25] KOYANAGI T, SPROUSTER D J, SNEAD L L,et al. X-ray characterization of anisotropic defect formation in SiC under irradiation with applied stress. Scripta Materialia, 2021, 197: 113785.
[26] 赵荣荣, 李连钢, 阮永丰. 中子辐照的6H-SiC单晶的退火回复特性. 河北师范大学学报: 自然科学版, 2018, 42(6): 488.
[27] SNEAD L L, NOZAWA T, KATOH Y,et al. Handbook of SiC properties for fuel performance modeling. Journal of Nuclear Materials, 2007, 371(1-3): 329.
[28] LIU H, CHAI Z F, WEI K R,et al. A study on the thermal conductivity of proton irradiated CVD-SiC and sintered SiC, measured using a modified laser flash method with multi-step machining. Journal of the European Ceramic Society, 2024, 44(11): 6305.
[29] YAN Z F, LIU R Z, LIU B,et al. Molecular dynamics simulation studies of properties, preparation, and performance of silicon carbide materials: a review. Energies, 2023, 16(3): 1176.
[30] AKIYOSHI M, TAKAGI I, YANO T,et al. Thermal conductivity of ceramics during irradiation. Fusion Engineering and Design, 2006, 81(1-7): 321.
[31] AL SMAIRAT S, GRAHAM J.Vacancy-induced enhancement of electron-phonon coupling in cubic silicon carbide and its relationship to the two-temperature model.Journal of Applied Physics, 2021, 130(12):125902.
[32] VASHISHTA P, KALIA R K, NAKANO A,et al. Interaction potential for silicon carbide: molecular dynamics study of elastic constants and vibrational density of states for crystalline and amorphous silicon carbide. Journal of Applied Physics, 2007, 101(10): 103515.
[33] ZHANG X Y, CHEN X F, WANG H,et al. Molecular dynamics analysis of chemical disorders induced by irradiated point defects in 6H-SiC. Journal of Inorganic Materials, 2020, 35(8): 889.
[34] QUILLIN K, SASIDHAR K N, QURESHI M W,et al. Unusual nanoscale amorphization of metallic chromium interfacing with SiC under high energy irradiation. Acta Materialia, 2024, 278: 120236.
[35] ZHANG S C, CUI X H, LIU H F,et al. Investigation of the recovery process in low-dose neutron-irradiated 6H-SiC by lattice parameter and FWHM of diffraction peak measurements. Radiation Effects and Defects in Solids, 2022, 177(7-8): 800.
[36] MADITO M J, HLATSHWAYO T T, MTSHALI C B.Chemical disorder of a-SiC layer induced in 6H-SiC by Cs and I ions co-implantation: Raman spectroscopy analysis.Applied Surface Science, 2021, 538: 148099.
[37] LEIDE A J, HOBBS L W, WANG Z Q,et al. The role of chemical disorder and structural freedom in radiation-induced amorphization of silicon carbide deduced from electron spectroscopy and ab initio simulations. Journal of Nuclear Materials, 2019, 514: 299.
[38] VALI I P, SHETTY P K, MAHESHA M G,et al. Electron and gamma irradiation effects on Al/n-4H-SiC schottky contacts. Vacuum, 2020, 172: 109068.
[39] LEWANDKÓW R, GRODZICKI M, MAZUR P,et al. Interface formation of Al₂O₃ on carbon enriched 6H-SiC (0001): photoelectron spectroscopy studies. Vacuum, 2020, 177: 109345.
[40] FELDMAN D W, PARKER J H, CHOYKE W J,et al. Phonon dispersion curves by Raman scattering in SiC, polytypes 3C, 4H, 6H, 15R, and 21R. Physical Review, 1968, 173(3): 787.
[41] 韩茹, 杨银堂, 柴常春. n-SiC 的电子拉曼散射及二级拉曼谱研究. 物理学报, 2008, 57(5): 3182.
[42] ZHANG S C, YANG Y, LIU H F,et al. Investigation of the recovery behavior of irradiation defects induced by a neutron in 4H-SiC combining Raman scattering and lattice parameters. Journal of Materials Research, 2022, 37(18): 2910.
[43] SORIEUL S, COSTANTINI J M, GOSMAIN L,et al. Raman spectroscopy study of heavy-ion-irradiated α-SiC. Journal of Physics: Condensed Matter, 2006, 18(22): 5235.
[44] CSÓRÉ A, VON BARDELEBEN H J, CANTIN J L,et al. Characterization and formation of NV centers in 3C, 4H, and 6H SiC: an ab initio study. Physical Review B, 2017, 96(8): 085204.
[45] LINEZ F, MAKKONEN I, TUOMISTO F.Calculation of positron annihilation characteristics of six main defects in 6H-SiC and the possibility to distinguish them experimentally.Physical Review B, 2016, 94(1): 014103.
[46] ZVANUT M E, VAN TOL J. Nitrogen-related point defect in 4H and 6H SiC. Physica B: Condensed Matter, 2007, 401-402: 73.
[47] KUATE DEFO R, ZHANG X, Y, BRACHER D,et al. Energetics and kinetics of vacancy defects in 4H-SiC. Physical Review B, 2018, 98(10): 104103.
[48] BARANOV P G, ILYIN I V, MUZAFAROVA M V,,et al. High-temperature stable multi-defect clusters in neutron irradiated silicon carbide: electron paramagnetic resonance study materials science forum. Trans Tech Publications Ltd, 2005, 483-485: 489.
[49] GERSTMANN U, RAULS E, FRAUENHEIM T,et al. Formation and annealing of nitrogen-related complexes in SiC. Physical Review B, 2003, 67(20): 205202.
[50] SON N T, IVANOV I G.Charge state control of the silicon vacancy and divacancy in silicon carbide.Journal of Applied Physics, 2021, 129(21): 215702.
[51] YANO T, FUTAMURA Y, YAMAZAKI S,et al. Recovery behavior of point defects after low-dose neutron irradiation at～ 423 K of sintered 6H-SiC by lattice parameter and macroscopic length measurements. Journal of Nuclear Materials, 2013, 442(1-3): S399.
[52] XI J Q, LIU B, YUAN F L,et al. Diffusion of point defects near stacking faults in 3C-SiC via first-principles calculations. Scripta Materialia, 2017, 139: 1.
[53] BOCKSTEDTE M, MATTAUSCH A, PANKRATOV O.Ab initio study of the annealing of vacancies and interstitials in cubic SiC: vacancy-interstitial recombination and aggregation of carbon interstitials.Physical Review B, 2004, 69(23): 235202.
[54] YANO T, YOU Y, KANAZAWA K,et al. Recovery behavior of neutron-irradiation-induced point defects of high-purity β-SiC. Journal of Nuclear Materials, 2014, 455(1-3): 445.