A kind of multilayer film protective coating, preparation method and application

Abstract

The invention provides a multilayer film protective coating, a preparation method and application thereof. The multilayer film protective coating is a Zr / Si multilayer film, wherein the Zr layer is the outermost layer of the multilayer film and is in a nanocrystalline form , the Si layer is under the Zr layer and has an amorphous structure, the Zr layer and the Si layer are arranged at intervals, the thickness of the Zr layer is in the range of 10-50nm, and the thickness of the Si layer is in the range of 10-100nm. A multi-layer film coating designed by the present invention is used for nuclear fuel cladding surface protection, or other anti-oxidation fields, and its design combines the advantages of a single coating such as mechanical properties and anti-oxidation properties, avoiding the disadvantages of a single-layer film, The interfacial layer can also act as a diffusion barrier layer to hinder the development of cracks and the internal diffusion of oxygen to slow down the rate of oxidation and corrosion. The important feature is that oxidation-resistant amorphous layers such as Zr‑Si‑O and silicide layers are formed at the interface during oxidation. The coating can effectively improve the oxidation resistance and corrosion resistance of the cladding.

Description

technical field [0001] 本发明涉及多层膜结构涂层,具体涉及一种多层膜防护涂层、制备方法及应用。 Background technique [0002] 目前锆合金是应用最为广泛的核燃料包壳材料。锆合金因具有较低的热中子吸收截面(0.18靶恩)、良好的核燃料兼容性、优异的力学加工性能、以及在高温高压水中良好的抗腐蚀性能等,被广泛应用于核反应堆的堆芯结构材料如燃料包壳、压力管、支架和孔道管等。核反应堆长期服役于复杂的工作环境中(中子辐照、高温高压水腐蚀、应力腐蚀、温度梯度等),可能会导致包壳的严重降解,从而损害材料的性能,降低使用寿命。福岛核事故发生的原因是,冷却剂缺失造成堆芯内温度急剧升高并伴随着水蒸气的产生,而锆合金与水蒸气发生剧烈反应释放大量的氢气,导致反应堆堆芯的熔化以及氢气的爆炸。表明了锆合金在事故条件下,并不能保持其完整性。 [0003] 为了提高燃料包壳的抗高温蒸汽氧化性,提出了两种主要的策略来缓和燃料包壳的氧化动力学行为,一是研发Fe基合金、MAX相和Mo合金等抗氧化的包壳备选材料;二是在锆合金表面制备具有抗高温氧化及耐腐蚀性能的涂层。但是新型燃料包壳的研发需要的周期较长,而涂层技术是短期内最有效的方式以提高锆合金在反应堆环境下的抗高温氧化性,而且不会改变目前UO2-Zr基合金燃料包壳的设计。目前抗高温氧化涂层的研究主要集中在FeCrAl、Cr基、MAX、陶瓷、以及硅化物涂层等。实验证明了涂层具有优异的抗高温蒸汽氧化、耐腐蚀以及抗辐照性能。 [0004] 单个涂层对锆合金抗高温蒸汽氧化性的提高依赖于涂层表面生成连续而致密的氧化物,但依然存在一些问题。比如制备的涂层内部存在缺陷,则氧气或者水蒸气会通过缺陷进入涂层内部,导致基底很快被氧化而失去保护作用。涂层中存在的晶界、缺陷也会成为氧化介质的快速扩散通道,进而加速氧化。而多层膜的设计结合了两种涂层的优异性能如抗氧化性,单个涂层中存在的缺陷可以通过多层膜界面得到中和,同时大量的界面可以阻止裂纹发展,氧的向内扩散,从而起到缓和燃料包壳的氧化动力学行为。 Contents of the invention [0005] 本发明提出了一种多层膜防护涂层、制备方法及应用,涂层制备采用远源等离子体溅射系统(HiTUS),该技术制备的涂层成分均匀、结构致密...

AI Technical Summary

Problems solved by technology

For example, if there are defects inside the prepared coating, oxygen or water vapor will enter the interior of the coating through the defects, causing the substrate to be quickly oxidized and lose its protective effect.

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