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(NO 3 ) 2 –0.06 M Y(NO 3 ) 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 (D 50) of 51.90 μm. The molar ratio of Y to Zr is 2.84:1. The YSZ powder is finer (D 50 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 H 2 O + 2e − → H 2 ↑ + 2OH − ; Zr 4+ + 4OH − + nH 2 O → Zr(OH) 4 ·nH 2 O↓; and Y 3+ + 3OH − + nH 2 O → Y(OH) 3 ·nH 2 O↓. The conductivity of electrolyte sintered by YSZ powders increases with rising temperature, reaching 0.038S cm −1 at 1000 °C.