Among the many active photothermal nanomaterials, tungsten-oxide-based materials have received considerable attention because of their unique oxygen defect structure, strong local surface plasma resonance (LSPR), and efficient light-to-heat conversion. They have also been reported to be suitable for a variety of applications such as catalysis, electronics, illumination, and gas sensors.
Synthesis of tungsten and tungsten oxide powders with controllable size and structure by reverse microemulsion-mediated synthesis methods has been reported. These nanoparticles have been characterized by transmission electron microcopy, X-ray diffraction, and thermal analysis.
The crystallite size of tungsten nanoparticles is about 2 to 3 nm. Various crystalline structures were observed under heating to different temperatures. Amorphous structures were observed at lower temperatures, and crystalline structures were observed when the tungsten oxide was heated above 400deg C.
A low-pressure, high-density hydrogen plasma generated using a novel dual plasma system was used to produce tungsten nanoparticles in a tungsten target at a tungsten cathode bias of
The use of tungsten nanoparticles to modify the microstructure of an Al-5Mg alloy is a possible strategy for increasing ultimate strength by the Orowan mechanism and simultaneously increasing plasticity by grain refinement of the alloy. Tungsten concentrations of 0.5 to 0.8 wt.% were tested, and a slight modification of the alloy microstructure and an increase in the spherical morphology of the Al5W phase was observed at higher tungsten content.