Mechanism of Reduced Sintering Temperature of Al₂O₃⁻ZrO₂ Nanocomposites Obtained by Microwave Hydrothermal Synthesis

Materials
Iwona KoltsovSwietlana Stelmakh

Abstract

A novel method to obtain Al₂O₃⁻ZrO₂ nanocomposites is presented. It consists of the co-precipitation step of boehmite (AlO(OH)) and ZrO₂, followed by microwave hydrothermal treatment at 270 °C and 60 MPa, and by calcination at 600 °C. Using this method, we obtained two nanocomposites: Al₂O₃⁻20 wt % ZrO₂ and Al₂O₃⁻40 wt % ZrO₂. Nanocomposites were characterized by Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. Sintering behavior and thermal expansion coefficients were investigated during dilatometric tests. The sintering temperatures of the nanocomposites were 1209 °C and 1231 °C, respectively-approximately 100 °C lower than reported for such composites. We attribute the decrease of the sintering temperature to the specific nanostructure obtained using microwave hydrothermal treatment instead of conventional calcination. Microwave hydrothermal treatment resulted in a fine distribution of intermixed highly crystalline nanoparticles of boehmite and zirconia. Such intermixing prevented particle growth, which is a factor reducing sintering temperature. Further, due to reduced grain growth, stability of the θ-Al₂O₃ phase was extended up to 1200 °C, which enhance...Continue Reading

References

Feb 12, 2015·Beilstein Journal of Nanotechnology·Agnieszka OpalinskaWitold Lojkowski
Jun 24, 2016·Beilstein Journal of Nanotechnology·Jacek WojnarowiczWitold Lojkowski

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Citations

Apr 5, 2019·Scientific Reports·Iwona KoltsovWitold Lojkowski
Mar 6, 2019·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Iwona KoltsovWitold Lojkowski

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Methods Mentioned

BETA
transmission electron microscopy

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FullProf

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