关键词: 钨酸铒;陶瓷;负热膨胀;固相法

Abstract: 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 X-ray 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-7.81×10-6 K-1 at 100-600 ℃ based on the HTXRD results.

Key words: Er2W3O12;ceramic;negative thermal expansion;solid state reaction method