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Published on: July 19, 2019
Boron modifications produced in an induction-coupled argon plasma
Science (New York, N.Y.)
|February 28, 1969
Summary
Microcrystalline boron particles processed in plasma transform into well-crystallized spheroids. New monocrystal and polycrystal boron forms were also discovered during this study.
Area of Science:
- Materials Science
- Solid State Chemistry
Background:
- Boron exhibits complex polymorphism.
- Understanding boron's crystalline structures is crucial for advanced material applications.
Purpose of the Study:
- To investigate the structural transformations of microcrystalline boron subjected to radio-frequency induction-coupled plasma.
- To identify any new crystalline forms of boron produced under these conditions.
Main Methods:
- Microcrystalline beta-rhombohedral boron particles (50-100 micrometers) were passed through an argon plasma.
- The plasma was maintained within a radio-frequency induction-coupled torch.
- Resulting particles were analyzed for crystalline structure and morphology.
Main Results:
- Most particles transformed into better-crystallized spheroids of the original beta-rhombohedral boron structure and similar size.
- Four distinct, well-faceted crystal habits were observed.
- These included monocrystals of beta-rhombohedral boron, tetragonal-III boron, and a novel cubic boron form.
- A fourth type consisted of polycrystals of another novel boron form, appearing as stacked hexagonal platelets.
Conclusions:
- Radio-frequency plasma treatment refines the crystallinity of beta-rhombohedral boron.
- The study identified previously unreported cubic and polycrystal forms of boron.
- These findings expand the known phase diagram of boron and suggest potential for novel boron allotrope synthesis.
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