Simple Preparation of Yttria‐Stabilized Zirconia Powders by Plasma Discharge Electrolysis in Nitrate Solution.

Yttria‐stabilized zirconia (YSZ) powder is widely used in battery and thermal barrier coatings. This article reports a method of preparing YSZ powder using plasma in air atmosphere at room temperature in 0.34 M ZrO(NO3)2–0.06 M Y(NO3)3 solution. Diverse characterization techniques are utilized to examine the morphology and composition of synthesized powders. Electrolytic green powder consists mainly of hydroxide, which is annealed to form a well‐crystallized YSZ oxide powder with coexisting tetragonal and cubic phases. The green powder is composed of micrometer‐sized particles, with a particle size distribution (D50) of 51.90 μm. The molar ratio of Y to Zr is 2.84:1. The YSZ powder is finer (D50 is 5.80 μm) with irregular nanoparticles aggregating together, and the molar ratio of Y to Zr is 2.57:1. Hydroxyl radicals (OH·) and hydrogen radicals (H·) are found in the flame during discharge electrolysis, and the main formation reactions of the powders by this process are H2O + 2e− → H2↑ + 2OH−; Zr4+ + 4OH− + nH2O → Zr(OH)4·nH2O↓; and Y3+ + 3OH− + nH2O → Y(OH)3·nH2O↓. The conductivity of electrolyte sintered by YSZ powders increases with rising temperature, reaching 0.038S cm−1 at 1000 °C. [ABSTRACT FROM AUTHOR]