Er_2W_3O_(12)陶瓷的制备及其负热膨胀性能研究

Preparation and Negative Thermal Expansion of Er_2W_3O_(12) Ceramics

以分析纯Er_2O_3和WO_3为原料,采用固相法制备Er_2W_3O_(12)陶瓷,并利用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)和热重分析仪(TG)对其结构组分、断面形貌和吸湿特性进行表征。采用热膨胀仪和变温XRD对Er_2W_3O_(12)陶瓷的负热膨胀特性进行表征。结果表明:在950℃烧结6 h制得的Er_2W_3O_(12)陶瓷结构致密。Er_2W_3O_(12)材料在室温下容易吸湿,在120℃完全失去吸湿水,表现为正交相的Er_2W_3O_(12)陶瓷,具有良好的负热膨胀性能,其在138~700℃的平均热膨胀系数为-7.94×10^(-6)K-1。变温XRD分析发现:Er_2W_3O_(12)陶瓷沿三个晶轴方向均表现为负热膨胀,在100~600℃温度区间内,Er_2W_3O_(12)陶瓷的热膨胀系数为-7.81×10^(-6)K-1。

Negative thermal expansion Er2W3O12 ceramics were successfully prepared,using solid state reaction of Er2O3 and WO3 as raw materials. The microstructure,composition and hygroscopicity of the Er2W3O12 samples were investigated by X-ray diffraction（ XRD）,field emission scanning electron microscopy（ FESEM） and thermogravimetric analysis（ TG）. The negative thermal expansion of the Er2W3O12 ceramics was studied using the thermal mechanical analysis（ TMA） and high temperature Xray diffraction（ HTXRD）. Results indicate that the Er2W3O12 ceramics sintered at 950 ℃ for 6 h are well crystallized. TG analysis shows that Er2W3O12 is hygroscopic. The dehydration starts at 120 ℃,and the Er2W3O12 crystals are in orthorhombic structure after dehydration. The orthorhombic Er2W3O12 ceramics show excellent negative thermal expansion. The thermal expansion coefficient of the orthorhombic Er2W3O12 ceramics is-7. 94 × 10^-6）K^-1 at 138-700 ℃. HTXRD results indicate that the Er2W3O12 ceramics show negative thermal expansion along three axes,and the average thermal expansion coefficient of the orthorhombic Er2W3O12 ceramics is calculated to be-7. 81 × 10^-6K^-1 at 100-600 ℃ based on the HTXRD results.