In Situ TEM Observation of Helium Bubbles Collapsing on Nanostructured Tungsten during Annealing
In Situ TEM Observation of Helium Bubbles Collapsing on Nanostructured Tungsten during Annealing
复制标题
退火过程中纳米结构钨上氦气泡破裂的原位 TEM 观察
DOI：
10.1585/pfr.11.1206125
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发表时间：
2016
影响因子：
0.8
通讯作者：
N. Ohno
中科院分区：
文献类型：
--
作者：
M. Yajima;N. Yoshida;S. Kajita;N. Ohno
众所周知，当钨（W）表面被He等离子体照射时，会发生强烈的形态和性质变化，例如氦（He）气泡[1-3]和模糊纤维状纳米结构[4，5]（下文称为“纳米结构”）的形成。研究表明，当温度在1000 - 2000 K范围内，入射离子能量高于20 eV时，就会形成纳米结构[6]。这些纳米结构在没有He离子照射的情况下加热到1000 K以上时重新整合到W的表面上[7-12]。在一项研究中，使用透射电子显微镜（TEM）观察了经过阶段加热的退火样品，发现在W的表面扩散期间，纳米结构的恢复发生在1173 K [13]。然而，在退火过程中的氦泡的行为和它们与纳米结构的坍塌的关系还有待确定。在这项研究中，我们研究了在退火过程中，使用一个特殊的TEM设备，使观察，而样品被加热的行为。我们的研究是第一个捕捉到氦泡在退火过程中破裂的时刻。此外，与以前的研究不同[13]，我们的纳米结构在退火过程中被碳包覆。这模拟了在实际退火过程中可能发生的沉积对纳米结构的影响。涂层的影响将在后面讨论。机械抛光粉末冶金W盘（Nilaco Co.，Ltd.）直径为5 mm、厚度为0.2mm的玻璃作为样品。在线性偏滤器等离子体模拟器NAGDIS（名古屋DIvertor Simulator）II中用He等离子体辐照抛光样品[14]。通过偏置样品来控制入射离子能量，其约为55 eV。样品在1330 K下暴露于He等离子体，最高达2.0 × 1025 m−2。
It is known that strong morphology and property changes, such as the formation of helium (He) bubbles [1–3] and fuzzy fiberform nanostructures [4, 5] (hereafter referred to as “nanostructures”), occur when tungsten (W) surfaces are irradiated by He plasma. Studies have revealed that nanostructures are formed when the temperature is in the range of 1000 2000 K and the incident ion energy is higher than 20 eV [6]. These nanostructures reintegrate onto the surface of W when heated above ∼1000 K without He-ion irradiation [7–12]. In a study, annealed samples subjected to heating in stages were observed using transmission electron microscopy (TEM), and it was found that the recovery of the nanostructures occurred at 1173 K during the surface diffusion of W [13]. However, the behavior of He bubbles during annealing and their relation to collapsing of the nanostructures are yet to be identified. In this study, we investigate the behavior of He bubbles during the annealing process using a special TEM device that enables observations to be made while the sample is being heated. Our study is the first to capture the moment when a He bubble bursts during annealing. Moreover, unlike previous studies [13], our nanostructures are coated by carbon during annealing. This simulates the effect of depositions, which can occur during an actual annealing processes, on the nanostructures. The influence of coating will be discussed later. Mechanically polished powder metallurgy W disks (Nilaco Co., Ltd.) with a diameter of 5 mm and a thickness of 0.2 mm were used as samples. The polished samples were irradiated with He plasma in the linear divertor plasma simulator NAGDIS (NAGoya DIvertor Simulator)II [14]. The incident ion energy was controlled by biasing the sample, and it was approximately 55 eV. The sample was exposed to He plasma at 1330 K up to 2.0 × 1025 m−2.
影响因子：
3.1
作者：
Nishijima, D;Ye, MY;Takamura, S
通讯作者：
Takamura, S
影响因子：
3.3
作者：
Kajita, Shin;Sakaguchi, Wataru;Saeki, Tsubasa
通讯作者：
Saeki, Tsubasa