Processing of dielectric oxynitride perovskites for powders, ceramics, compacts and thin films

Abstract

PERSPECTIVE This journal is © The Royal Society of Chemistry 2013Dalton Trans., 2013, 00, 1-3 | 1 Oxynitride perovskites having oxide and nitride anions together in a compound, are a new class of dielectric material. The shaping process in either the bulk ceramics or thin films is an essential factor for investigating and utilizing the dielectric properties. In this perspective, recent studies on the shaping of dielectric oxynitride perovskites are reviewed with consideration of powder preparation and thermal stability for sintering, several sintering methods, ultra-high pressure compaction, and thin-film formation.

High-Temperature Synthesis and Dielectric Properties of LaTaON2

“…4 Dielectric permittivity (ε r ) in centrosymmetric pseudocubic perovskites has been reported for a limited number of compounds, with values ranging from 16 for NdHfO 2 N 5 to 4900 for SrTaO 2 N. 6 The large permittivity values were earlier interpreted by the presence of local B−X (X = O and N) dipoles induced by the partial anion order; 7−9 however it has been recently emphasized that some of the reported gigantic ε r values may not be intrinsic but resulting from spurious effects due to poor sintering of the measured samples and leakage contributions. 10 The synthesis of perovskite oxynitrides has been mostly performed under NH 3 (g) at temperatures between 900−1000 °C. 11 The starting compounds are either ternary oxides or a mixture of oxides and carbonates.…”

Octahedral and trigonal-prismatic coordination preferences in Nb-, Mo-, Ta-, and W-based ABX2 layered oxides, oxynitrides, and nitrides

“…Even though there are potential applications, most of the reported properties include the effects of the surface layers, impurities, and grain connections. For the synthesis of oxynitrides and nitrides, a major approach is to heat (typically above 600-1000 °C) the oxide, sulfide, or chloride precursors under an ammonia flow; in these reactions, the temperature profile and ammonia flow rate should be kinetically controlled [12,[71][72][73]. Single crystals of several ABX2 compounds have been grown using flux methods (LiNbO2 [74,75], CaNb2O4 [47], and NaNbN2 [76]); however, many ABX2 compounds are only available in the powder form.…”

Structure, Optical, and Photocatalytic Properties of Oxynitride Solid Solutions Ca1–xSrxNbO2N, CaNb1–xTaxO2N, and SrNb1–xTaxO2N Prepared from Soft‐Chemistry Precursors

“…Quarternary perovskite oxynitrides have been investigated for a number of possible applications such as pigments, semiconductors and dielectrics, LED phosphors, and in particular as photocatalysts for solar wastewater treatment,, air purification, or water splitting …”

“…Quarternary perovskite oxynitrides have been investigated for a number of possible applications [1] such as pigments, [2][3][4][5] semiconductors and dielectrics, [6][7][8][9] LED phosphors [10,11] and in particular as photocatalysts for solar wastewater treatment, [12,13] air purification, [14] or water splitting. [15][16][17] A wide variety of parameters can be adjusted to tailor the properties of oxynitrides, for example particle size or ammonolysis conditions.…”