Innovative sintering process for fabrication of thermochromic smooth VO2 ceramics
Language
en
Article de revue
This item was published in
Journal of Alloys and Compounds. 2022, vol. 890, p. 161890 (9 p.)
Elsevier
English Abstract
In this paper, a pyrolysis method is used to synthesize high quality VO2 powder. Black carbon and V2O5 powder are mixed and annealed at 650 °C or 800 °C under argon flow to initiate a carbo-reduction reaction. The 650 °C ...Read more >
In this paper, a pyrolysis method is used to synthesize high quality VO2 powder. Black carbon and V2O5 powder are mixed and annealed at 650 °C or 800 °C under argon flow to initiate a carbo-reduction reaction. The 650 °C VO2 powder presents submicron particle size with an amorphous fraction estimated at 11.5%. With the increase of the annealing temperature up to 800 °C, grains become larger than the micron while the crystallinity goes up to 98.5% (i.e. amorphous fraction drops to 1.5%). This one-step process allows the preparation of quantities up to 10 g of VO2 powder and should be easily transferable to large-scale production. An innovative sintering process is then adopted to produce high quality thermochromic VO2 ceramics from the as-prepared VO2 powder. First, SPS process is used to obtain high-density VO2 pellet. Then, the VO2 pellet is post-annealed in a homemade induction furnace at 1300 °C under a controlled atmosphere to allow grain growth by coalescence and improve pellet surface quality. According to a surface topography analysis, the mean amplitude roughness parameter (Ra) of the obtained VO2 ceramic is found to be 2.93 ± 0.01 nm. A large resistance change by three orders of magnitude along the phase transition is observed, which makes the as-prepared smooth VO2 ceramic a promising candidate for various applications requiring optical and/or electronic switching behavior depending on temperature.Read less <
English Keywords
Vanadium dioxide
large-scale powder synthesis
sintering process
smooth ceramic
thermochromic behaviour
Origin
Hal imported