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Preparation of nanocrystalline heterostructures TiO2-SnO2 by modified sol-gel method

Marzec A., Pędzich Z., Maziarz W.

Mechanik

2016

R. 89, nr 5-6

506--507

The paper presents production of TiO2-SnO2 nanocom-posites with the use of sol-gel method combined with hydrothermal processing of the formed hydroxide gel. As proven by XRD analysis, both oxides crystallise in tetragonal systems: TiO2–anatase, SnO2–cassiterite. Mean sizes of the crystallites are TiO2 ~30÷40 nm and SnO2 ~3÷4 nm, respectively. Moreover, the produced TiO2-SnO2 nanocomposites are characterised by a high specific surface area (~100 m2/g).

W pracy opisano otrzymywanie nanokompozytów TiO2-SnO2 metodą zol-żel połączoną z obróbką hydrotermalną otrzymanego żelu wodorotlenkowego. Analiza XRD wykazała, że obydwa tlenki krystalizują w strukturach tetragonalnych: TiO2–anataz, SnO2–kasyteryt. Średnie wielkości krystalitów wynoszą odpowiednio TiO2 ~30÷40 nm, SnO2 ~3÷4 nm. Ponadto, otrzymane nanokompozyty TiO2-SnO2 charakteryzują się dużym rozwinięciem powierzchni właściwej (~100 m2/g).

Nano-ceramic aspect of preparation and processing of zirconia nanopowders

Pyda W.

Materials Science Poland

2008

Vol. 26, No. 2

403--412

The hydrothermal method of preparation of zirconia nanopowders was reviewed with respect to the influence of solution pH, mineralizer and TiO2 concentration on the composition and morphology of zirconia crystallite phase. The pH dependence of both the ratio of the needle-shaped monoclinic to oval tetragonal zirconia nano-crystallites and CaO concentration in the zirconia solution has been described. Compressibility improvement and sinterability deterioration of zirconia nanopowders due to the presence of needle-shaped crystallites have been shown. Hydrothermal crystallisation of zirconia nanopowders with a mineralizer-dependent amount of the tetragonal and monoclinic zirconia polymorphs composed of oval and elongated crystallites with various ratios or plate-shaped crystallites has been discussed. The effect of TiO2 on hindered hydrothermal crystallisation of zirconia solid solutions was shown. A potential of the in-situ method for shaping the nano-structure of the TiC/ZrO2 composites has been presented. A slight effect of the carbon precursor and a significant one of the carbon incorporation way on the morphology of TiC in-situ inclusions have been documented.

Micropowders for the Ca-TZP Materials - the Role of Solution pH during Hydrothermal Crystallisation

Pyda W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

1999

Vol. 47, nr 4

397-409

A hydrothermal synthesis was used to prepare zirconia ultrafine powders stabilised with 6 mol % CaO. The influence of pH of a coprecipitation and crystalisation environment on the chemical composition and morphology of resultant powders was studied. Behaviour of the powders during compaction and sintering was characterised. The crystallisation mechanisms in the NaOH environment were discussed. Requirements to be met by the powders for Ca-TZP materials have been determined.