Flux growth of baryte-type BaSO4 from chloridic alkaline metal solvents

Ehrentraut, Dirk; Pollnau, Markus

doi:10.1016/s0022-0248(01)01693-1

Cited by 9 publications

(9 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, we used the ternary NaCl-KCl-CsCl solvent [12,11]. The solvent composition corresponds to the eutectic point of the ternary system [22] with a eutectic temperature of 482…”

Section: Selection Of the Solventmentioning

confidence: 99%

“…Small but rather high-quality crystals of all these compounds can be prepared by crystallization from alkali-metal chloride solutions [7][8][9][10][11]. Such a flux growth is possible at temperatures much lower than the melting points of u Fax: +41-21/693-3701, E-mail: yaroslav.romanyuk@epfl.ch the molybdates, tungstates, and sulfates, thus offering specific advantages over growth from the melts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Low-temperature flux growth of sulfates, molybdates, and tungstates of Ca, Sr, and Ba and investigation of doping with Mn 6+

et al. 2004

Self Cite

View full text Add to dashboard Cite

“…Therefore, we used the ternary NaCl-KCl-CsCl solvent [12,11]. The solvent composition corresponds to the eutectic point of the ternary system [22] with a eutectic temperature of 482…”

Section: Selection Of the Solventmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low-temperature flux growth of sulfates, molybdates, and tungstates of Ca, Sr, and Ba and investigation of doping with Mn 6+

et al. 2004

Self Cite

View full text Add to dashboard Cite

“…In other fields, such as crystal growth, some fluxes have been found to be helpful to modify the shape of crystals [8,9]. Furthermore the solubility of the crystalline phase into the liquid flux has been identified as a key parameter [11]. This paper deals with the elaboration of the LaCeT phosphor thanks to the interaction between a precursor chemically homogeneous and with a controlled particles size distribution with different fluxes : Li 3 PO 4 , Li 2 CO 3 , Na 2 CO 3 , K 2 CO 3 .…”

Section: Introductionmentioning

confidence: 99%

Effect of different fluxes on the morphology of the LaPO4:Ce, Tb phosphor

et al. 2005

View full text Add to dashboard Cite

Abstract. LaPO 4 :Ce, Tb (LaCeT) is a green phosphor used in fluorescent lamps and plasma display panels. In order to improve the fabrication process of this phosphor, different fluxes have been used. Their influence on the particles size and shape is described thanks to SEM analyses. Fluxes were found to control the morphology of particles : LaCeT particles, from spherical to parallelepiped-like shape, with suitable sizes, from 0.1 to 10 µm, have been synthesized. Furthermore the photoluminescence emission of the obtained powders has been checked, and it has been proved that the effect of the fluxes studied is not harmful to the LaCeT final optical properties. . Improvement of the morphology control is of great interest and different ways are tried in order to achieve this aim [1][2][3]. In fact, size and shape of the phosphor particles have an important influence on the emission intensity and the efficiency of the device [4]. Phosphor particles should be non-aggregated and their particles size distribution should range between 1 to 8 µm depending on the application. This morphology is required for the coating technique, which enhances the compactness of the powder and thus, the brightness of the device [1,4]. LaPO 4 :Ce, Tb (LaCeT), is a green phosphor which fluorescent lamps (FL) is the main application. In order to coat the lamps surface, the inside of the tube is put into contact with a suspension containing the LaCeT powder [5]. So, the phosphor grains should have a size as homogeneous as possible and above all without any aggregates nor agglomerates. Otherwise dispersion and sedimentation problems could occur. Moreover an optimal compactness of the powder is suitable in order to enhance the brightness of the display and to enable to lower the production cost. In order to improve the efficiency of the phosphors, the surface particles should also be as smooth as possible and a high crystallization degree is required. In the industry, phosphors are generally elaborated from oxides or carbonates by a solid state reaction : a high temperature heat treatment with or without fluxes. But this synthesis method does not allow an efficient control of the chemical homogeneity, neither the morphology of the phosphor particles without a grinding step, harmful to its optical properties [2,6]. The use of precursors elaborated by the wet method (rare earth phosphates, rare earth borates,…), has been a breakthrough for the control of the phosphor particles size distribution. In order to control the particles morphology, fluxes as Li 3 PO 4 , Li 2 CO 3 , K 2 CO 3 , MgF 2 , are added to the phosphor precursor and then the powder is fired at high temperature [1,7]. This KEY-WORDS

show abstract

“…The ternary NaCl-KCl-CsCl eutectic mixture [12] was employed as a solvent. This solvent was previously applied to the growth of BaSO 4 :Mn 6+ [13][14][15][16]. This chloride mixture with a melting point of 480 C allows growth temperatures as low as 540 C, which is about 300 C lower than typical growth temperatures from the tungstate solutions mentioned above.…”

Section: Introductionmentioning

confidence: 99%