An oxalate–peroxide complex used in the preparation of dopedbarium titanate

Gijp, S. van der; Winnubst, Louis; Verweij, H.

doi:10.1039/a801466c

Cited by 13 publications

(8 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These three regimes have also been reported for oxalate complexation methods used to synthesize barium titanates. 22,23 The exothermic peak at 550 ³C in the DTA curve, as well as the small exothermic peaks at 730, 820, 870, and 935 ³C, do not correspond to weight changes in the TG curve. Therefore, these peaks are attributed to solid-state reactions.…”

Section: Calcination Behaviourmentioning

confidence: 97%

“…Calcining at temperatures over 1000 ³C required that the resulting powder be ground. After calcination, the oxide powders were pressed into pellets with a diameter of 13 mm using cold uniaxial pressing (300 kg cm 22 ). In order to achieve a better compact after pressing, a binder (Hoechst wachs C micro binder) was added to the mixture (2 wt%).…”

Section: Sample Preparationmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of the preparation of In-doped CaZrO3 using a peroxo-oxalate complexation method

Rij

Winnubst

et al. 2000

J. Mater. Chem.

Self Cite

View full text Add to dashboard Cite

The wet chemical synthesis of CaZr 0.9 In 0.1 O 32a powders via a peroxo-oxalate complexation method has been studied in detail using different techniques, i.e. TG-DTA, XRD, FT-IR, BET, SEM, EDX, and non-isothermal densi®cation. Using these techniques, the different reaction steps in the calcination process have been clari®ed. After drying the precipitated complex at 150 ³C for 3 h, a mixture of calcium oxalate and an amorphous zirconia phase is found. Between 200 and 450 ³C, the calcium oxalate decomposes into calcium carbonate. In the temperature range 450±800 ³C, the calcium carbonate decomposes into CaO, while a crystalline zirconia phase appears (CaZr 4 O 9 ). In this temperature range, the formation of CaZrO 3 is already observed. Further increasing the calcination temperature to 1000 ³C leads to a binary mixture of CaZrO 3 and CaIn 2 O 4 . When the calcination temperature is increased to around 1500 ³C, the CaIn 2 O 4 phase dissolves into the calcium zirconate to form the desired CaZr 0.9 In 0.1 O 32a . All compacts sintered at 1550 ³C for 10 h show single-phase CaZr 0.9 In 0.1 O 32a , independent of the calcination temperature. The morphology of the sintered compacts, however, varies with the calcination temperature, due to the presence or absence of a reactive sintering step around 1300 ³C. Powders calcined at 1000 ³C show a larger grain size in the sintered compact than powders calcined at 1450 or 1550 ³C.

show abstract

Section: Calcination Behaviourmentioning

confidence: 97%

Section: Sample Preparationmentioning

confidence: 99%

Analysis of the preparation of In-doped CaZrO3 using a peroxo-oxalate complexation method

Rij

Winnubst

et al. 2000

J. Mater. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…This color diminishes with increasing pH of the solution after addition, and the solution eventually becomes colorless at pH 8.5 and 10. Since a small amount of titanium peroxo complex in aqueous solution results in a red color, 9 the change in color of the filtrate from red at pH 4.5 to colorless at pH 8.5 and 10 indicates that at low pH titanium-peroxo complexes remain dissolved, whereas Ti 0.91 Zr 0.09 (O 2 )(C 2 O 4 ) 2− is formed at high pH, 8 which is thermally more stable than the complex without oxalate. 13 At low pH another complex, Ti(O 2 )OH + , is formed which does react with barium to give an insoluble complex.…”

Section: (1) Influence Of Phmentioning

confidence: 99%

“…Because of the change in pH from 3 to 9 and the presence of hydrogen peroxide and oxalate, the structure of the complex changes to Ti 0.91 Zr 0.09 O 2 (C 2 O 4 ) 2− . 8 Therefore, the formation of the precipitating complex can be described as follows: Next to the processes described above, a side reaction may also occur, condensation of the zirconium and titanium components. Condensation reactions occur at both high and low pH.…”

Section: (2) Influence Of Precipitation Temperature With Alkoxide Prementioning

confidence: 99%

“…2 A suitable wet-chemical preparation technique for Zr-doped BaTiO 3 is the complexation and subsequent precipitation of a titanium peroxo-oxalate species in an aqueous environment. 8 In this process, barium ions react with a dissolved titanium/zirconium complex: In the present paper the question is addressed whether it is possible to improve the materials performance any further by using a preparation route that will lead to more homogeneous materials. Such a route should obviously include a wetchemical homogeneous powder preparation process.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Peroxo‐oxalate Preparation of Doped Barium Titanate

Gijp

Winnubst

Verweij

1999

Journal of the American Ceramic Society

Self Cite

View full text Add to dashboard Cite

The peroxo-oxalate complexation method is a method that can be used for the preparation of doped barium titanate. In this paper we focus on BaTi 0.91 Zr 0.09 O 3 , which can be used for discharge capacitors in lamp starters. The preparation method described here is based on the complexation and subsequent precipitation in basic environment of Ba, Ti, and Zr ions with hydrogen peroxide and oxalate. The influence of several process parameters, like precipitation temperature and pH, on powder properties is described. A single-phase perovskite crystal structure is obtained after calcination starting from a chloride precursor solution using a precipitation temperature of 40°C and a pH of 9. Because the peroxo-oxalate process starts with inexpensive chlorides and is performed in air, the peroxo-oxalate process is suitable for the commercial production of doped barium titanate.

show abstract