提高铀抗氢化性能的碳氧离子组合注入

Suppression of Uranium-hydrogen Reaction by Ion Implantation With Carbon and Oxygon Ions

利用离子注入方法,将CO_2气体离解后的离子,在不同能量、束流下注入贫铀表面。利用俄歇能谱仪(AES)分析改性层中元素的浓度分布,用低角度X射线衍射仪(GAXRD)分析离子注入层的结构。在t=100℃、p=0.2 MPa条件下,利用铀-氢气体反应测试离子注入C、O后贫铀的铀氢反应孕育期,用扫描电镜(SEM)观察试样氢化反应前后的表面形貌。结果表明:注入C、O离子后,形成了结构致密的改性层。在35 kV/8～9 mA/3 h(注入能量/注入束流/注入时间)注入条件下,改性层由UO_2和石墨C组成;在65 kV/8～9 mA/3 h和3 kV/80 mA/3 h注入条件下,改性层为UO_2和少量UC。UO_2和UC为低氢渗透材料,抑制了氢向基体界面的迁移和渗透,从而降低了氢化物在界面形核和长大的几率,增强了铀抗氢化性能。氢化反应后,空白贫铀试样表面出现较多的蚀坑,并造成大面积脱落,而注入样品的表面仅出现较少孤立的蚀点。

Decomposed CO2 gas is implanted to uranium at different energy, beam current and temperature. The Auger electron spectromy (AES) and globe angle X-ray diffraction (GAXRD) are applied to analyze the element distribution and phase structure of modified layers. The induction time is investigated on implanted sample by uranium-hydrogen reaction at 100 ℃ and 0. 2 MPa conditions. The surface micrography is investigated by scanning electron spectromy (SEM) before and after uranium-hydrogen reaction. The results show that the modified layer implanted with oxygen and carbon ions consists of UO2 and C at the condition of 35 kV/8-9 mA/3 h, UO2 and small UC at the conditions of 65 kV/8~9 mA/3 h and 3 kV/80 mA/3 h. The induction of the implanted sample increases significantly, because the UO2 and UC modified layers retard to the production nuclei and growth of hydride. The depleted uranium has macros flake on sur- face, but the implanted samples have isloated spots after uranium react with hydrogen.