Sc2W3O12/ZrO2可控热膨胀复合材料的制备

采用固相法成功制备了纯度较高的各向异性负热膨胀材料Sc₂W₃O₁₂。将ZrO₂与Sc₂W₃O₁₂按一定体积比混合, 在1200 ℃烧结10 h制备Sc₂W₃O₁₂/ZrO₂复合材料。通过XRD、SEM、EDS和热膨胀仪对合成样品的晶体结构、断面形貌和热膨胀性能进行表征。结果表明: 样品组元为正交相Sc₂W₃O₁₂和单斜相ZrO₂; 在 30~600 ℃内, Sc₂W₃O₁₂/ZrO₂复合材料的热膨胀系数皆线性一致, 并且通过改变Sc₂W₃O₁₂的体积分数, 其热膨胀系数可以控制为正、负或零, 其中60%Sc₂W₃O₁₂/ZrO₂复合材料在30~600 ℃的平均热膨胀系数为0.026×10^-6 ℃^-1, 近似为0。

Synthesis of Sc2W3O12/ZrO2 composites with controllable thermal expansion

Sc2W3O12 which exhibits excellent anisotropic negative thermal expansion was synthesized using solid-state reaction. Sc2W3O12/ZrO2 composites were prepared by mixing ZrO 2 and Sc2W3O12 at different volume ratios and sintered at 1200 ℃ for 10 h. The crystal structure, fracture surface morphology and thermal expansion properties of the synthesized samples were characterized by XRD, SEM, EDS and dilatometer. The results indicate that the obtained samples contain only orthorhombic Sc2W3O12 and monoclinic ZrO2 phase without other phases. All the thermal expansion properties of Sc2W3O12/ZrO2 composites are linear in 30-600 ℃ and their thermal expansion coefficients can be controlled as positive, negative or even zero by adjusting the volume fraction of Sc2W3O12 . 60%Sc2W3O12/ZrO2 composite shows almost zero thermal expansion, and its average thermal expansion coefficient is 0.026×10 -6 ℃ -1 in 30-600 ℃.