Tungsten nanoparticles with controlled shape and crystallinity obtained by magnetron sputtering and gas aggregation

• Published in: Materials letters 2017-08, Vol.200, p.121-124
• Main Authors: Acsente, T., Negrea, R.F., Nistor, L.C., Matei, E., Grisolia, C., Birjega, R., Dinescu, G.
• Format: Article
• Language: English
• Subjects: Agglomeration; Crystal structure; Dendritic structure; Gas aggregation; Magnetron sputtering; Materials science; Nanocrystals; Nanoparticles; Particle shape; Radio frequency; Stability; Tungsten
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2017.04.105

[Display omitted] •Synthesis of tungsten nanoparticles with concave hexapod and cube-octahedral shapes is reported.•The hexapod nanoparticles present a dendritic growth.•The cube-octahedral nanoparticles present a single crystal structure.•Enhanced stability of the β-W phase in hexapod nanoparticles is reported. We report the synthesis of tungsten nanoparticles with two distinct shapes, concave hexapods and faceted cube-octahedral nanocrystals. These types of nanoparticles were obtained with a cluster source based on magnetron sputtering and gas aggregation, by supplying the magnetron discharge with continuous or pulsed wave radiofrequency power. Detailed morphological and microstructural studies were performed. The hexapod particles present a dendritic growth while the faceted ones have a single crystal structure. The α-W and β-W crystalline phases are present in both types of nanoparticles; nevertheless, the β-W structure is dominant for the hexapod ones. Although the β-W phase is usually metastable, we observed its unexpected long term preservation in hexapod nanoparticles. The results, added to previously reported nanoflower-like particles, point out the ability to control the shape and structure of the tungsten nanoparticles using the magnetron sputtering gas aggregation technique.