石墨烯复合陶瓷阻氚涂层增韧机理研究

Tritium as the smallest radionuclide and main fuel for the future fusion, is easy to permeate through metallic materials. That could cause the embrittlement of structural materials and finally influence the safety of fusion reactor. Fabrication of ceramic coating (aluminium oxide, erbium oxide, etc.) as tritium permeation barrier (TPB) on the structural materials surface was an effective method to prevent the tritium from permeating. However, brittleness has remained a problem with ceramic coating. The ceramic coating would easy crack and spall due to thermal stress cumulative damage. It eventually affects the service life. As an emerging nanomaterial, graphene can not only be used for toughening ceramic materials, but also impermeable for tritium atom. Hence, graphene is a promising material for TPB. In this project, graphene/erbium oxide composite coating with dense and homogeneous microstructure is prepared on CLAM steel substrate by sol-gel method. The effect of graphene content on microstructure and properties of graphene/erbium oxide composite coating will be investigated in this project. With the microstructure analysis, especially crack initiation and expansion behavior, the toughening mechanism of graphene/erbium oxide composite coating will be clarified. The proposed researches would provide a deep understanding of the toughening mechanism for graphene/ceramic composite coating and guidelines for the design of TPB. The proposed researches have wide application prospect and eventually promote the development of TPB.

氚是聚变堆的主要燃料，也是原子半径最小的放射性核素，在大多数金属材料中具有很强的渗透性。氚渗透不仅对材料造成严重的脆化效应，也严重威胁聚变堆氚自持与安全。在金属结构材料表面制备氧化铝、氧化铒等陶瓷阻氚涂层，是目前解决氚渗透的主要手段，但是陶瓷涂层的韧性需要进一步改善，以减少长期服役过程中偶发裂纹对阻氚性能的影响，延长涂层使用寿命。石墨烯作为新兴的纳米材料，不仅可作为增强相用于陶瓷材料增韧，且自身亦不能透过氚原子，是一种前景广阔的阻氚材料。本申请项目拟利用溶胶-凝胶法在中国低活化抗辐照钢（CLAM）表面制备石墨烯复合氧化铒阻氚涂层，研究石墨烯含量对氧化铒陶瓷涂层组织性能的影响规律，通过分析涂层中裂纹在石墨烯附近的萌生与扩展行为，结合分析动力学模拟，阐明石墨烯复合氧化铒阻氚涂层增韧机理。本项目的研究成果将为长寿命阻氚涂层研制提供支持，在氚防护领域具有广泛的应用前景。

氚是聚变堆的主要燃料，也是原子半径最小的放射性核素，在大多数金属材料中具有很强的渗透性。氚渗透不仅对材料造成严重的脆化效应，也严重威胁聚变堆氚自持与安全。在金属结构材料表面制备氧化铝、氧化铒等陶瓷阻氚涂层，是目前解决氚渗透的主要手段，但是陶瓷涂层的韧性需要进一步改善，以减少长期服役过程中偶发裂纹对阻氚性能的影响，延长涂层使用寿命。石墨烯作为新兴的纳米材料，不仅可作为增强相用于陶瓷材料增韧，且自身亦不能透过氚原子，是一种前景广阔的阻氚材料。本申请项目利用溶胶-凝胶法在中国低活化抗辐照钢（CLAM）表面制备石墨烯复合陶瓷（包括氧化铒和氧化铝）阻氚涂层，研究了不同陶瓷材料的石墨烯复合涂层制备工艺，获得致密、均匀及结合力高的石墨烯复合陶瓷涂层。通过研究石墨烯含量对复合涂层组织性能的影响规律，结合微观结构表征分析涂层中裂纹在石墨烯附近的萌生与扩展行为，阐明石墨烯复合陶瓷阻氚涂层增韧机理。最后通过研究不同石墨烯含量对复合涂层氘渗透性能的影响规律，获得最佳的石墨烯配比，研究表明添加0.5 wt% 石墨烯复合涂层的阻氘性能与纯Al2O3涂层相比提高了约9倍。本项目的研究成果将为长寿命阻氚涂层研制提供支持，在氚防护领域具有广泛的应用前景。