Preparation of Potential Protonic Conductor Yttria Doped Hafnia by Using the Modified Solid State Reaction Method

Abstract

A pure and well crystalized yttrium doped hafnium oxide Hf 0.69 Y 0.31 O 2-δ (YSH) is obtained by using a modified solid state reaction method, where a water-based milling medium and freeze drying are implemented to reduce the agglomeration. The mean sizes of the YSH powder, which is obtained through a traditional alcohol-based milling method, is more than 1 um. However, the powder size can be reduced to 100 nm by using the water-based milling method. In addition, the calcination temperature can be lowered 200 ℃ to get a pure phase by using the water-based milling method, compared to the alcohol-based milling method. The relative density of YSH ceramic materials can reach to 97.5% by conventional sintering at 1650 ℃ after during 10 h.

The effect of NiO on the conductivity of BaZr0.5Ce0.3Y0.2O3−δ based electrolytes

“…An improved solid-state reaction method, which included a water-based milling followed by a freeze drying process, was applied for the powder preparation [33][34][35] . Take BZCY(Ni)532 for example, stoichiometric amounts of raw materials BaCO3, ZrO2, CeO2, Y2O3 and NiO (≥ 99.9% purity, Alfa Aesar GmbH & Co KG, Germany) were ball-milled for 5 h. After that, the powder mixture slurry was dried by freeze drying.…”