- Title
- Preparation of lanthanum hexaboride cathodes for thermionic energy generation
- Creator
- Hasan, M. M.; Kisi, E.; Sugo, H.
- Relation
- 2013 International Conference on Informatics, Electronics & Vision (ICIEV). Proceedings of 2013 International Conference on Informatics, Electronics & Vision (ICIEV) (Dhaka, Bangladesh 17-18 May, 2013)
- Publisher Link
- http://dx.doi.org/10.1109/ICIEV.2013.6572545
- Publisher
- Institute of Electrical and Electronics Engineers (IEEE)
- Resource Type
- conference paper
- Date
- 2013
- Description
- Due to low work function, high melting point and superior chemical stability at high temperatures, lanthanum hexaboride (LaB) has great potential as a thermionic emitter in renewable energy applications. The main challenge is to synthesise these hexaborides at lower temperatures without any post-synthesis cleaning treatments. In this present work, we investigated several techniques to prepare pure lanthanum hexaboride using different blends of lanthanum oxide (LaO)-boron (B), LaO -B-carbon (C), LaO-boron carbide (B C) blends, respectively. The starting powders for each blend were mixed by milling for 20 to 30 min and pressed as pellets. Additionally, several samples of LaO-boron blends were prepared by high-energy milling (HEM) for 16 hours. Subsequently, the pellets were placed in a tube furnace at different temperatures under a moderate vacuum to undergo solid state reactions. The synthesised products were investigated for the structural, morphological and thermionic properties using X-ray diffraction (XRD), scanning electron microscope (SEM), electron dispersive spectroscopy (EDS) and a Schottky apparatus. We are able to synthesis pure LaB at comparably lower temperatures via all the investigated methods. Pure LaB is found to be synthesised as low as 1250 °C via the method using high-energy milling. XRD and SEM analyses revealed that LaB prepared using these methods were nanocrystalline. Thermionic emission measurements show that pure LaB is found to possess a low Richardson work function of 2.64 eV making it suitable for producing high current density cathodes.
- Subject
- high-energy milling (HEM); thermionic energy converter (TEC); structure; morphology; work function
- Identifier
- http://hdl.handle.net/1959.13/1293988
- Identifier
- uon:18716
- Identifier
- ISBN:9781479903979
- Language
- eng
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