Thermal expansion behaviors of yttrium tungstates in the WO3–Y2O3 system
Thermal expansion behaviors of yttrium tungstates in the WO3–Y2O3 system
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DOI：
10.1016/j.ceramint.2013.04.024
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发表时间：
2013-09
影响因子：
5.2
通讯作者：
J. Koh;Erinn Sörge;Tzu-Chien Wen;D. Shetty
中科院分区：
文献类型：
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作者：
J. Koh;Erinn Sörge;Tzu-Chien Wen;D. Shetty
全致密的多晶氧化钇（Y2 O3）在整个中间范围（3-5 µm）内具有高红外（IR）透射率和低发射率，但由于其低强度和高热膨胀系数（CTE），缺乏高性能航空航天应用的抗热震性。通过分散Y2 W3 O 12相，试图开发一种低CTE和高强度的Y2 O3复合材料，Y2 W3 O 12已知表现出高负CTE。然而，Y2 O3和Y2 W3 O 12的烧结混合物不形成稳定的两相复合物。烧结混合物形成新的富Y2 O3相，如Y2 WO 6和Y 6 WO 12，这取决于Y2 O3和WO 3的相对量。这些钨酸钇的热膨胀行为的研究表明，它们具有高的CTE与纯Y2 O3相媲美。以Y2 O3为基体，以负CTE的钨酸钇为分散相，获得近零CTE复合材料的目标在该体系中无法实现。
Fully-dense, polycrystalline yttria (Y2O3) exhibits high infrared (IR) transmittance in the full mid range (3–5 µm) with low emittance, but lacks thermal-shock resistance for high-performance aerospace applications due to its low strength and high coefficient of thermal expansion (CTE). An attempt was made to develop a low CTE and high strength composite of Y2O3by dispersing the phase, Y2W3O12, known to exhibit a high negative CTE. The sintered mixture of Y2O3and Y2W3O12, however, does not form a stable, two-phase composite. The sintered mixture forms new Y2O3-rich phases, such as Y2WO6and Y6WO12, depending on the relative amounts of Y2O3and WO3. Investigation of the thermal-expansion behaviors of these yttrium tungstates revealed that they have high CTEs comparable to pure Y2O3. The goal of obtaining a near-zero CTE composite with Y2O3as the matrix and a yttrium tungstate with a negative CTE as the dispersed phase cannot be realized in this system.