低能氦等离子体低温条件下钨材料的表面形貌

为研究氦等离子体在钨表面造成的表面纳米结构，利用荷兰基础能源研究所Pilot-PSI直线等离子体发生装置在673 K温度下，对钨材料进行了低能（40 eV）高束流强度（4×10²³ m^-2?s^-1）氦等离子体辐照。实验结果表明，辐照后钨材料表面出现了多种不同形态的纳米结构，表面纳米结构和晶粒的表面法向之间存在明显关联。在表面法向为［111］的晶粒表面出现三角形的纳米结构，在［110］取向的晶粒表面出现条带状的纳米结构，而在［001］取向的晶粒表面没有明显的结构出现。晶粒表面的纳米结构尺寸在50 nm左右，高度起伏在5 nm以下。另外，氦等离子体辐照会造成晶界处的高度差，在25 nm左右。分析推测氦等离子体辐照造成的晶粒表面和晶界的形貌可能是由近表面的气泡所导致的。

Surface Morphology of W Surface Exposed to Low Energy He Plasma at Low Temperature

In order to investigate the surface nanostructures induced by helium plasma on tungsten surface ,tungsten samples were exposed to low energy (40 eV) and high flux (4 × 1023 m -2 · s-1 ) helium plasma at 673 K in Pilot‐PSI linear plasma device of Dutch Institute for Fundamental Energy Research .Experimental results show that after exposure to helium plasma ,surface nanostructures with different morphologies appear on tungsten surface , and the surface nanostructures show strong dependence on the surface normal direction .Triangular structures are observed on surfaces with 111] sur‐face normal direction ,and lamellar structures are observed on 110] surfaces ,w hile no obvious structures are observed on 001] surfaces .The lateral sizes of nanostructures are about 50 nm ,and the height of surface nanostructures is lower than 5 nm .In addi‐tion ,fluctuations appear along the grain boundaries ,and the height difference of w hich is about 25 nm .The surface morphology on tungsten surface is speculated to be due to the helium bubbles in the near surface region .