Publication detail

The effect of O2 impurity on surface morphology of polycrystalline W during low-energy and high-flux He+ irradiation

Liu, L., Li, S., Liu, D., Benstetter, G., Man, O., Michalicka, J., Zhang, Y., Hong, Y., Fan, H., Ni, W., Yang, Q., Wu, Y., Bi, Z.

Original Title

The effect of O2 impurity on surface morphology of polycrystalline W during low-energy and high-flux He+ irradiation

Type

journal article in Web of Science

Language

English

Original Abstract

The interaction between the impurities (such as carbon, nitrogen, oxygen) and the plasma-facing materials (PFMs) can profoundly influence the performance and service of the PFMs. In this paper, we investigated the influence of oxygen (O2) impurity in the helium radio frequency (RF) plasma on the surface morphology of polycrystalline tungsten (W) irradiated at the surface temperature of 1450 ± 50 K and the ion energy of 100 eV. The pressure ratio of O2 to He (R) in RF source varied from 4.0 × 10−6 to 9.0 × 10-2. The total irradiation flux and fluence were ˜1.2 × 1022 ions·m-2·s-1 and ˜1.0 × 1026 ions·m-2, respectively. After He+ irradiation, the specimen surface morphology was observed by scanning electron microscopy. It was found that with increasing R from 4.0 × 10−6 to 9.0 × 10-2 the thickness of nano-fuzz layer at the W surface was thinner and thinner, accompanied by the formation of rod-like structures. The erosion yield increased from 5.2 × 10-4 to 2.3 × 10-2 W/ion when R varied from 4.0 × 10-6 to 9.0 × 10-2. The X-ray diffraction analysis shows that tungsten oxides were formed at the near surface of specimens when R exceeded 1.8 × 10-2. The erosion yield measurements revealed that in addition to surface physical sputtering process, the chemical erosion process could occur due to the interaction between oxygen-containing species and W at the surface. The results indicated that the presence of O2 impurity in He plasma can obviously affect the surface microstructure of W. The study suggested that O2 impurity can effectively reduce the growth of nano-fuzz structures.

Keywords

Plasma-facing materials Tungsten Helium ion irradiation

Authors

Liu, L., Li, S., Liu, D., Benstetter, G., Man, O., Michalicka, J., Zhang, Y., Hong, Y., Fan, H., Ni, W., Yang, Q., Wu, Y., Bi, Z.

Released

8. 1. 2019

Publisher

Elsevier B.V.

Location

Netherlands

ISBN

0920-3796

Periodical

FUSION ENGINEERING AND DESIGN

Year of study

139

Number

February 2019

State

Swiss Confederation

Pages from

96

Pages to

103

Pages count

8

URL

https://www.sciencedirect.com/science/article/pii/S0920379619300031?via%3Dihub

BibTex

@article{BUT160718,
  author="Lu {Liu} and Li {Shouzhe} and Liu {Dongping} and Günther {Benstetter} and Ondřej {Man} and Jan {Michalička}",
  title="The effect of O2 impurity on surface morphology of polycrystalline W during low-energy and high-flux He+ irradiation",
  journal="FUSION ENGINEERING AND DESIGN",
  year="2019",
  volume="139",
  number="February 2019",
  pages="96--103",
  doi="10.1016/j.fusengdes.2019.01.003",
  issn="0920-3796",
  url="https://www.sciencedirect.com/science/article/pii/S0920379619300031?via%3Dihub"
}