Microwave synthesis of ZrO₂ and Yttria stabilized ZrO₂ particles from aqueous precursor solutions

Abstract

Zirconia and Yttrium stabilized zirconia are well-known ceramic materials. Scaling down the dimension of these ceramics can result in a faster sintering process at lower temperatures. Microwave synthesis of nano-structured particles is a very attractive synthesis route because of the short synthesis time and low reaction temperature. This allows a fast screening of the influence of different parameters such as time, temperature and pressure on the final size and crystal phase of the particles. In this study Zr and Zr/Y aqueous precursors are mixed with a variety of complexing agents or surfactants in different ratios. The reason is twofold: (1) we aim for a stable precursor solution which is established by lowering the free ion concentration and (2) we want to see the influence of the complexing agents on the growth of the particles and the formation of crystalline phases. Particle sizes of these particle vary from 40 -200 nm. The crystallinity is confirmed by X-ray diffraction. The stabilization of these particles and possible exchange of the ligands is examined with NMR measurements (1D -proton combined with 2D NOESY) and is compared with TGA-DTA analysis of the isolated particles.

Aqueous ZrO2 and YSZ Colloidal Systems through Microwave Assisted Hydrothermal Synthesis

“…After purification PEG1000 was found neither in the solution nor on the particles. Despite the absence of ligands in the colloidal solution, the ZrO 2 suspension remains stable [ 29 ]. As the pH level of this suspension is around 0.9, thus very acidic and not suited for industrial applications, an attempt was made to raise the pH.…”