锆合金包壳表面涂层的制备进展

Progress in Preparation of Zirconium Alloy Cladding Surface Coatings

锆因其极低的中子吸收截面、较高的熔点和优良的耐腐蚀性等特点,在核技术领域得到大量应用,主要作为核燃料的包壳材料。2011年日本福岛核事故后,事故容错燃料(ATF)的开发成为研究热点,尤其着重提高包壳材料的抗高温氧化性,而在锆合金表面制备涂层是提高该能力的重要途径之一。评述了锆合金包壳表面涂层的种类、性能、制备方法及各种方法的特点与发展。指出激光熔覆、等离子喷涂和冷喷涂都有沉积速率快、涂层厚的特点,但涂层过厚将降低核燃料的中子经济性。激光熔覆和等离子喷涂制得的涂层内应力大,存在较多气孔甚至微裂纹。冷喷涂涂层的应力和气孔得到改善,但喷涂法都存在粉尘及噪声污染等问题。重点分析了磁控溅射法(MS)和电弧离子镀(AIP)两种物理气相沉积技术在包壳涂层制备中的应用现状、存在的问题及未来发展方向。指出磁控溅射法因沉积速率可控、涂层的内应力小及涂层组分可调整等优势而应用最广。电弧离子镀因涂层致密、结合力强而最具发展潜力。这为进一步促进锆合金表面涂层的制备与研究提供了参考。

Zirconium is widely used in nuclear technology as the cladding materials of nuclear fuel because of its very low neutron absorption cross section,high melting point and excellent corrosion resistance.After the Fukushima nuclear accident in Japan in 2011,the development of accident tolerant fuel(ATF)has become a research hotspot,particularly focusing on improving the oxidation resistance of cladding materials at high temperature.Surface coating of zirconium alloy is one of the significant ways to improve the ability.The types,properties,preparation methods,characteristics and development of zirconium alloy cladding surface coatings were reviewed.It was pointed out that laser cladding,plasma spraying and cold spraying all had the characteristics of high deposition rate and large coating thickness,but too large coating thickness reduced the neutron economy of nuclear fuel.The coatings obtained by laser cladding and plasma spraying had large internal stress,many pores and even micro-cracks.The stress and pores of cold spray coating were decreased.There were some problems in spraying process,such as dust and noise pollution.The application status,existing problems and future development of magnetron sputtering(MS)and arc ion plating(AIP)in physical vapor deposition technology,were emphatically analyzed in the preparation of cladding coatings.It was pointed out that magnetron sputtering was most widely used because of the advantages of controllable deposition rate,low internal stress of coating and adjustable coating composition.Arc ion plating has the most development potential because of its compact coating and strong binding force.It provides a reference for further promoting the preparation and research of zirconium alloy surface coating.