Tailorable thermal expansion and hygroscopic properties of cerium-substituted Y2W3O12 ceramics

A new series of cerium-substituted Y2W3O12 ceramics were first fabricated with the goal of tailoring the thermal expansion and reducing the hygroscopicity. Influence of cerium substitution on the structure, hygroscopicity and thermal expansion property of Y2W3O12 ceramics were investigated using XRD, FESEM, HRTEM, XPS, TGA and TMA. Results indicate that the Y3+ can partly be substituted by Ce3+ in Y2-xCexW3O12 ceramics and increasing substitution of Y3+ in Y2W3O12 by Ce3+ results in the crystal structure change from orthorhombic to monoclinic. Single-phase Y2-xCexW3O12 ceramics can be synthesized in the range of 0.0 ≤ x ≤ 0.25 with an orthorhombic Y2W3O12-type crystal structure and 1.0 < x ≤ 2.0 with monoclinic Ce2W3O12-type crystal structure, respectively. As the amount of substituted cerium increases, the hygroscopic phenomenon of Y2-xCexW3O12 is significantly promoted, meanwhile the coefficient of thermal expansion gradually decreases. The linear coefficient of thermal expansion of Y2-xCexW3O12 ceramics can be adjusted from −13.094 × 10−6 K−1 to 2.327 × 10−6 K−1 by changing the substituted amount of cerium. Moreover, Y0.25Ce1.75W3O12 does not absorb moisture in air and shows almost zero thermal expansion from 182 °C to 700 °C and its coefficient of thermal expansion is tested to be −0.820 × 10−6 K−1. This low thermal expansion Y0.25Ce1.75W3O12 material may have great potential applications in manufacturing precision device in many fields.