Hard and tough nitrogen doped tungsten coatings deposited by HIPAC: Microstructure and mechanical properties

作者：Zou, Gaopeng; Hong, Yue; Wang, Shuqin; Yin, Shiheng; Lei, Shumei; Wang, Yi; Zhu, Huichao; Kuang, Tongchun^*; Zhou, Kesong

来源：Journal of Alloys and Compounds, 2021, 876: 160146.

DOI：10.1016/j.jallcom.2021.160146

• N doped bcc-W coatings
• HIPAC
• Hardness
• Toughness
• Tribological performance

The hardness and toughness of W-N coating deposited by conventional magnetron sputtering (CMS) usually cannot be improved simultaneously. In this paper, a nitrogen (N) doped approach using high ionized plasma assisted coating (HIPAC) technology was used to challenge the inversion relationship. Reference pure W coatings were also deposited using the same process parameters without nitrogen. The effect of N dopants on the microstructure, mechanical and tribological properties of N-doped W(N) coatings was systematically investigated by electron microscopic methods, indenter tests and ball-on-disc sliding tests. The results indicate that the W(N) coatings have higher hardness, better toughness, more compact surface and finer columnar crystallites compared to pure W coatings. The preferred orientation changes from (110) to (222) with introducing N dopants. No brittle W-N compounds are detected in W(N) coatings. TEM observations reveal that part of the N dopants in W(N) coatings exist as solute atoms in the alpha-W solid solution, and the others are aggregated as N-clusters. Hence W(N) coatings can get the ceramic hardness (similar to 30 GPa) and retain the metallic toughness. Benefiting from the high hardness, good toughness and reduced friction coefficient (similar to 0.42), the wear rate coefficient of W(N) coatings is one order of magnitude lower than W coatings. Compared to the reported C and B atoms doped W(C/B) coatings produced by CMS, the W(N) coatings deposited by HIPAC in this paper can give a competitive strategy to achieve better mechanical properties.

• 单位
  广东省人民医院; 仲恺农业工程学院