Hexaborides of the rare-earth metals

Samsonov, G. V.; Paderno, Yu. B.; Fomenko, V. S.

doi:10.1007/bf00774188

Cited by 32 publications

(21 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The borides of the Group IIIA elements (Sc, Y, 1 2 La, and the rare earth metals) have been examined several times [1][2][3][4] since Lafferty showed in 1951 that the IIIA hexaborides, and LaB6 in particular, showed great promise as electron emitters [5]. Most effort has gone into LaB6 but this has not so far led to the production of large single crystals.…”

Section: Introductionmentioning

confidence: 99%

On the growth and properties of single crystal LaB4

Deacon

Hiscocks

1971

J Mater Sci

View full text Add to dashboard Cite

A technique has been developed for the growth of single crystals of lanthanum tetraboride LAB,, from solution in La. Under optimum conditions, crystal size is limited by the size of the crucible. Lattice parameters, thermal expansion coefficient, and microhardness are reported and the growth facets have been identified. An initial check on the electron emitting properties have shown them to be comparable with those of LAB6.

show abstract

Section: Introductionmentioning

confidence: 99%

On the growth and properties of single crystal LaB4

Deacon

Hiscocks

1971

J Mater Sci

View full text Add to dashboard Cite

show abstract

“…The borothermal method produces highly volatile boron oxide (BO) as a by-product [6]. Therefore, a preliminary investigation was carried out to see the effect of excess boron on the quality of synthesised products.…”

Section: Resultsmentioning

confidence: 99%

“…They can be prepared by a simple borothermal method in which their oxides are reduced by boron [5,6]. This solid-state reaction process requires very high temperatures (1500-1700°C) and produces coarsegrained LaB6 and CeB6.…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Synthesis of Rare-Earth Hexaborides for Solar Energy Conversion

Hasan

Sugo

Kisi

2014

MATEC Web of Conferences

View full text Add to dashboard Cite

Abstract. Thermionic energy conversion is an ideal way of converting concentrated solar energy into electricity. Developing suitable emitter/collector materials, with optimum work functions whilst being able to withstand elevated temperatures under high vacuum conditions, is a major challenge. Rare-earth hexaborides have great potential as thermionic emitters due to their superior chemical stability and low work function values, lanthanum hexaboride (I~2.60eV) and cerium hexaboride (I~2.60eV). This study forms part of a series of investigations aimed at developing rare-earth hexaboride cathode materials. Methods used to synthesise, characterise and fabricate these materials are discussed together with electron emission results.

show abstract

“…Lanthanum hexaboride (LaB 6 ) has attracted significant interest in the last 60 years amongst transition metal borides and rare-earth metal borides (Samsonov et al, 1963;Paderno et al, 1979;Xu et al, 2012;Dou et al, 2012). LaB 6 is a refractory ceramic material characterized by high melting point, high strength, high chemical and thermal stability, low vapor pressure, low electronic work function, low resistivity, low thermal expansion coefficient, high transmission stability, high current and voltage capability and high neutron absorbability (Gao et al, 2005;Xu et al, 2006;Zhang et al, 2008;Selvan et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Preparation of LaB<sub>6</sub> Powders via Calciothermic Reduction using Mechanochemistry and Acid Leaching

Ağaoğulları

Balcı

Öveçoğlu

et al. 2016

KONA

View full text Add to dashboard Cite

This study reports a room temperature mechanochemical route for the synthesis of LaB 6 powders originated from related metal oxide powders as La 2 O 3 and B 2 O 3 . Ca granules and B 2 O 3 powders were respectively used as reducing agent and boron source in the experiments. This study is actually meaningful to create added value by using the native boron source of Turkey for the production of high-technology boron materials. Milling duration as the most important parameter of mechanochemistry was examined to reveal the ideal production conditions. Mechanochemically synthesized powders were subjected to selective HCl leaching in order to eliminate unwanted phases. Thermochemical software of HSC Chemistry TM program was utilized to determine the reaction probability and to estimate the predicted products. Characterization investigations were carried out by X-ray diffractometer (XRD), differential scanning calorimeter (DSC), particle size analyzer (PSA), stereomicroscope (SM), scanning electron microscope (SEM), transmission electron microscope/energy dispersive spectrometer (TEM/EDS) and atomic absorption spectrometer (AAS). Nanosized LaB 6 powders were achieved with/without an insignificant amount of Ca 3 (BO 3 ) 2 phase via mechanochemistry in a high-energy ball mill for 3 h and via leaching with 4 M and 6 M HCl. Lastly, the experimental outputs obtained by a calciothermic reduction were compared with those of magnesiothermic reduction.

show abstract

Hexaborides of the rare-earth metals

Cited by 32 publications

References 2 publications

On the growth and properties of single crystal LaB4

On the growth and properties of single crystal LaB4

Low Temperature Synthesis of Rare-Earth Hexaborides for Solar Energy Conversion

Preparation of LaB<sub>6</sub> Powders via Calciothermic Reduction using Mechanochemistry and Acid Leaching

Contact Info

Product

Resources

About