Effect of Ba concentration on phase stability and mechanical and thermal properties of La₂Mo₂O₉

详细信息    查看全文

• 作者：Kyung Min Ok^a ; Yuji Ohishi^a ; ^{ohishi@see.eng.osaka-u.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Hiroaki Muta^a ; Ken Kurosaki^a ; Shinsuke Yamanaka^a ; ^b
• 关键词：DSC ; Differential scanning calorimetry ; TBCs ; Thermal barrier coatings ; TECs ; Thermal expansion coefficients ; XRD ; X-ray diffraction ; YSZ ; Yttria-stabilized zirconia
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：37
• 期：1
• 页码：281-288
• 全文大小：2075 K

文摘

Ba-substituted La₂Mo₂O₉ ((La_1−xBa_x)₂Mo₂O_9−δ, x = 0–0.12) was prepared and the thermal and mechanical properties were evaluated. The thermal expansion coefficients (TECs) were determined from high-temperature X-ray diffraction (XRD) analysis. Phase transition in La₂Mo₂O₉ was suppressed via substitution of Ba for La, as demonstrated by differential scanning calorimetry (DSC) analysis. The mechanical properties, such as the bulk modulus, shear modulus, Young’s modulus, compressibility, and Debye temperature were evaluated from the measured sound velocities. The thermal conductivity was evaluated from the thermal diffusivity, heat capacity, and density in the temperature range from room temperature to 1073 K. The thermal conductivity decreased with increasing Ba content. Theoretical calculations based on the Klemens–Callaway model were performed to analyze the thermal conductivity, and the results suggest that the reduction of the thermal conductivity was mainly attributed to oxygen defects in the anion sublattice of La₂Mo₂O₉.