Mixed hydroxide precursors for La2Ti2O7 and Nd2Ti2O7 by homogeneous precipitation

M. Suresh; A. V. Prasadarao; Sridhar Komarneni

doi:10.1023/A:1011464902626

Mixed hydroxide precursors for La₂Ti₂O₇ and Nd₂Ti₂O₇ by homogeneous precipitation

M. Suresh, A. V. Prasadarao, Sridhar Komarneni

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23 Scopus citations

Abstract

Feasibility of formation of stoichiometric precursors of either M₂ (TiO)₂(C₂O₄)₅ 4H₂O (M = La and Nd) or coprecipitated hydroxides of M(OH)₃+TiO(OH)₂ was investigated by two solution routes at different pH values. Composition of precipitates obtained at pH = 7.0 by coprecipitation method starting from La or Nd nitrates and potassium titanyl oxalate corresponded to a physical mixture of La or Nd(C₂O₄)₃ 9.5H₂O and TiO(OH)₂·H₂O which on thermal decomposition did not yield phase pure M₂Ti₂O₇. However, precipitation from La or Nd nitrates and titanium tertrachloride by urea hydrolysis yielded homogeneous mixture of hydroxides of La or Nd and Ti, which on pyrolysis at 950°C yielded phase pure La₂Ti₂O₇ and Nd₂Ti₂O₇. Use of potassium titanyl oxalate as precursor for Ti, led to selective precipitation of La or Nd oxalate even at pH as low as 0.1 leading to sequential precipitation of La or Nd oxalate followed by Ti hydroxide at pH = 3.0. The resultant precipitate on pyrolysis underwent typical solid-state reaction.

Original language	English (US)
Pages (from-to)	147-151
Number of pages	5
Journal	Journal of Electroceramics
Volume	6
Issue number	2
DOIs	https://doi.org/10.1023/A:1011464902626
State	Published - Apr 1 2001

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Condensed Matter Physics
Mechanics of Materials
Materials Chemistry
Electrical and Electronic Engineering

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title = "Mixed hydroxide precursors for La2Ti2O7 and Nd2Ti2O7 by homogeneous precipitation",

abstract = "Feasibility of formation of stoichiometric precursors of either M2 (TiO)2(C2O4)5 4H2O (M = La and Nd) or coprecipitated hydroxides of M(OH)3+TiO(OH)2 was investigated by two solution routes at different pH values. Composition of precipitates obtained at pH = 7.0 by coprecipitation method starting from La or Nd nitrates and potassium titanyl oxalate corresponded to a physical mixture of La or Nd(C2O4)3 9.5H2O and TiO(OH)2·H2O which on thermal decomposition did not yield phase pure M2Ti2O7. However, precipitation from La or Nd nitrates and titanium tertrachloride by urea hydrolysis yielded homogeneous mixture of hydroxides of La or Nd and Ti, which on pyrolysis at 950°C yielded phase pure La2Ti2O7 and Nd2Ti2O7. Use of potassium titanyl oxalate as precursor for Ti, led to selective precipitation of La or Nd oxalate even at pH as low as 0.1 leading to sequential precipitation of La or Nd oxalate followed by Ti hydroxide at pH = 3.0. The resultant precipitate on pyrolysis underwent typical solid-state reaction.",

author = "M. Suresh and Prasadarao, {A. V.} and Sridhar Komarneni",

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T1 - Mixed hydroxide precursors for La2Ti2O7 and Nd2Ti2O7 by homogeneous precipitation

AU - Suresh, M.

AU - Prasadarao, A. V.

AU - Komarneni, Sridhar

PY - 2001/4/1

Y1 - 2001/4/1

N2 - Feasibility of formation of stoichiometric precursors of either M2 (TiO)2(C2O4)5 4H2O (M = La and Nd) or coprecipitated hydroxides of M(OH)3+TiO(OH)2 was investigated by two solution routes at different pH values. Composition of precipitates obtained at pH = 7.0 by coprecipitation method starting from La or Nd nitrates and potassium titanyl oxalate corresponded to a physical mixture of La or Nd(C2O4)3 9.5H2O and TiO(OH)2·H2O which on thermal decomposition did not yield phase pure M2Ti2O7. However, precipitation from La or Nd nitrates and titanium tertrachloride by urea hydrolysis yielded homogeneous mixture of hydroxides of La or Nd and Ti, which on pyrolysis at 950°C yielded phase pure La2Ti2O7 and Nd2Ti2O7. Use of potassium titanyl oxalate as precursor for Ti, led to selective precipitation of La or Nd oxalate even at pH as low as 0.1 leading to sequential precipitation of La or Nd oxalate followed by Ti hydroxide at pH = 3.0. The resultant precipitate on pyrolysis underwent typical solid-state reaction.

AB - Feasibility of formation of stoichiometric precursors of either M2 (TiO)2(C2O4)5 4H2O (M = La and Nd) or coprecipitated hydroxides of M(OH)3+TiO(OH)2 was investigated by two solution routes at different pH values. Composition of precipitates obtained at pH = 7.0 by coprecipitation method starting from La or Nd nitrates and potassium titanyl oxalate corresponded to a physical mixture of La or Nd(C2O4)3 9.5H2O and TiO(OH)2·H2O which on thermal decomposition did not yield phase pure M2Ti2O7. However, precipitation from La or Nd nitrates and titanium tertrachloride by urea hydrolysis yielded homogeneous mixture of hydroxides of La or Nd and Ti, which on pyrolysis at 950°C yielded phase pure La2Ti2O7 and Nd2Ti2O7. Use of potassium titanyl oxalate as precursor for Ti, led to selective precipitation of La or Nd oxalate even at pH as low as 0.1 leading to sequential precipitation of La or Nd oxalate followed by Ti hydroxide at pH = 3.0. The resultant precipitate on pyrolysis underwent typical solid-state reaction.

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Mixed hydroxide precursors for La₂Ti₂O₇ and Nd₂Ti₂O₇ by homogeneous precipitation

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