Hydrothermal Synthesis of Ytterbium Silicate Nanoparticles

A simple, low-cost hydrothermal method was developed to synthesize 20-nm-diameter single-crystalline ytterbium silicate (Yb(2)Si(2)O(7) and Yb(2)SiO(5)) nanoparticles at 200 degrees C. This is nearly 1000 degrees C lower than that for the typical sol-gel route to ytterbium silicate powders. Obtained powders showed very low thermal conductivity, a suitable thermal expansion coefficient, and excellent thermal/structural stability, suggesting a potential application to environmental and thermal barrier coatings. Special focus was placed on assessing the hydrothermal reaction mechanism for particle formation.