Liquid‐Phase Sintering of Nanocrystalline Titania Doped with Boron Oxide: Bulk Versus Thin Film

Abstract

Boron oxide with a melting point of 4501C was used as an additive to study liquid-phase sintering of nanocrystalline titania, both in bulk as well as in thin films. The liquid phase has two salient effects. (I) It leads to enhanced transformation of anatase to rutile in the bulk material, accompanied by strong grain growth, and thus to a reduction in the densification rate with the anatase. (II) In the rutile, the liquid phase leads to a strongly increased densification rate in the bulk, but a reduced densification rate in the thin film. The latter is suggested to be caused by excellent wetting and low grain-boundary energies, leading to extended grain-boundary grooving and very rough surfaces of the thin film. The transition of boron oxide, once enhancing and once reducing the densification rate, is suggested to be related to the ratio of grain size to film thickness.

Fine‐Tuning the Acid–Base Properties of Boron‐Doped Magnesium Oxide Catalyst for the Selective Aldol Condensation

“…The addition of small quantities of acidic oxides (e.g., TiO 2 , Al 2 O 3 , B 2 O 3 ) can be used to adjust the basicity of the catalyst by reducing the strength of basic sites and providing acid sites . In previous studies, this doping has been typically accomplished by either coprecipitation of the two metal precursors or impregnation of the basic oxide with a solution of an acidic oxide precursor, followed by thermal treatment . However, these processes may lead to the formation of mixed oxides with low surface area, limited pore connectivity, and phase segregation.…”

Frequency-temperature dependent dynamics of dielectrics in ferric oxoborate Fe3BO6 of cocktail structure of nanorods

“…Our group used devitrification of series of iron borate glasses with different catalytic additives that tailors useful properties in small fibrils of ferrites, iron borates, or borates depending upon annealing in air [16,17]. Liquid B 2 O 3 , 450 C melting point, helps to grow archived facets of crystallites on a liquid-phase sintering at moderate temperature [18,19]. A low-viscosity fluid spreads around and wets growing crystallites so that they grow on nascent surfaces.…”