非晶FeW合金镀层的有序化现象及其新功能探索研究

发布时间：2018-05-04 18:42

  本文选题：非晶FeW合金镀层 + 真空扩散焊　； 参考：《北京科技大学》2016年博士论文

【摘要】：核能是一种主要的传统化石燃料的清洁替代能源。在核能应用领域中,材料问题是其能否最终实现的关键问题之一。核能的主要形式有两种：核聚变能和核裂变能。在聚变材料中,面向等离子体材料(Plasma Facing Material,PFM)是决定聚变能能否开发成功的关键材料。其中进一步提高PFM的综合性能和增强PFM与铜基热沉材料的连接性能是急需解决的两个难题。在核裂变领域,压水堆是世界上最早开发的动力堆堆型,也是目前世界上应用最广泛的裂变反应堆堆型。在压水堆中,材料需要承受高温高压以及核反应所产生的辐射等。苛刻的服役环境对材料提出了更高的要求。非晶FeW合金镀层是一种具有优异耐蚀性的功能性合金镀层,已经在工业领域获得广泛的应用。同时,非晶FeW合金镀层也是一种可以用于核能领域的潜在材料。本文从FeW非晶合金镀层的有序化转变和新功能探索两方面出发,研究了不同电镀工艺对非晶合金镀层的影响；有序化过程中,研究了温度对镀层表面形貌、结构、耐蚀性的影响；研究了基于非晶FeW合金镀层为中间层的异种金属连接问题：探索研究了非晶镀层的耐辐照腐蚀行为及表面疏水化改性。具体的研究工作及成果如下：(1)采用直流电镀工艺和双脉冲电镀工艺制备出FeW非晶合金镀层。采用直流电镀法时,当电流密度增大至0.1 A/cm2时,镀层颗粒明显长大,同时伴随较浅的凹坑产生;当电流密度进一步增大至0.5 A/cm2时,镀层表面颗粒明显减小,同时伴随大量微米孔洞产生。采用脉冲电镀法时,当正向占空比为10%,反向占空比为30%时,获得了表面相对致密均匀的非晶镀层。(2)考察了真空条件下,热处理温度对镀层表面形貌、结构、耐蚀性的影响。当热处理温度为700℃时,FeW合金镀层完全晶化。当热处理温度为500℃时,耐蚀性最好。(3)首次提出采用非晶FeW合金镀层作为中间层,通过真空扩散焊接工艺实现W板和Cu板、W/Cu合金的扩散连接。当焊接温度为950 ℃时,焊接界面的抗拉强度大于146 MPa。获得的新型W/Cu-PFM模块可承受4 h的短脉冲等离子体的原位辐照。并且利用此工艺已经成功的将其模块放大至100 mm×100 mm,完全满足偏滤器对实际模块的尺寸要求。(4)首次研究了非晶FeW合金镀层的伽马辐照腐蚀行为。在辐照的条件下,产生了具有强氧化性的辐照分解产物(如H2O2),因此镀层中Fe元素和W元素在腐蚀过程中的反应路径有所差别：此外,在辐照条件下测得的腐蚀电位明显高于未辐照样品。(5)对均匀多孔的直流镀层,在经过500℃、600℃不同温度热处理后,用十七氟癸基三甲氧基硅烷修饰,并获得粗糙度分别为82.2、117.5,接触角分别111°±1°、134°±1°的疏水表面。且修饰后所获得疏水表面的耐蚀性高于未修饰的亲水表面。
[Abstract]:Nuclear energy is a major clean alternative to traditional fossil fuels. In the field of nuclear energy application, the material problem is one of the key questions whether it can be finally realized. There are two main forms of nuclear energy: nuclear fusion energy and nuclear fission energy. Plasma Facing material is the key material to determine the successful development of fusion energy in fusion materials. Among them, it is urgent to improve the comprehensive properties of PFM and strengthen the bonding properties of PFM and copper-based heat sink materials. In the field of nuclear fission, PWR is the earliest type of power reactor developed in the world, and it is also the most widely used type of fission reactor in the world. In PWR, materials are subjected to high temperature and high pressure and radiation from nuclear reactions. The harsh service environment puts forward higher requirements for materials. Amorphous FeW alloy coating is a functional alloy coating with excellent corrosion resistance and has been widely used in industrial field. At the same time, amorphous FeW alloy coating is also a potential material for nuclear energy. In this paper, the effect of different electroplating processes on amorphous alloy coating is studied from the aspects of ordering transformation and new function exploration of FeW amorphous alloy coating, and the effect of temperature on the surface morphology and structure of amorphous alloy coating is studied in the process of ordering. The influence of corrosion resistance, the problem of dissimilar metal bonding based on amorphous FeW alloy coating as intermediate layer was studied. The radiation corrosion resistance and surface hydrophobic modification of amorphous FeW alloy coating were investigated. The specific research work and results are as follows: (1) FeW amorphous alloy coating is prepared by DC electroplating and double pulse electroplating. When the current density is increased to 0. 1 A/cm2, the coating particles grow up obviously, and the shallow pits are produced, and when the current density is further increased to 0. 5 A/cm2, the surface particles of the coating decrease obviously. At the same time, it is accompanied by a large number of micron holes. The effect of heat treatment temperature on the surface morphology, structure and corrosion resistance of the coating was investigated under vacuum condition when the positive duty cycle was 10 and the reverse duty cycle was 30. The amorphous coating with relatively dense and uniform surface was obtained under the condition of vacuum. When the heat treatment temperature is 700 鈩，

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