Preferred Orientations of Crystalline Phases Formed by Heat Treatments of BaO-B_2O_3-Fe_2O_3 Amorphous Oxides

BaO-B_2O_3-Fe_2O_3非晶氧化物热处理形成晶相的优选取向

• 批准号: 61550523
• 负责人: SEKI Fumie
• 金额: $ 1.22万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61550523/
• 关键词: Amorphous oxide; Preferred orientation; Crystallization; Crystallographic texture

A method is studied to control crystallographic textures of ceramic materials. Thin ribbon-like and 1 mm thick button-like specimens were made of molten 35mol%BaO-47mol%B_2O_3-18mol%Fe_2O_3 and 37mol%BaO-40mol%B_2O_3-23mol%Fe_2O_3 oxides by rapid solidification using single roll quenching and pressing between two permanent moulds, respectively. The specimens were examined by X-ray analysis and temperatures of crystallization (Tx1 and Tx2) were determined by DTA method. The ribbon-like specimens were crystallized in a uniformly heated furnace, while the button-like ones were sandwiched between hot and cold metal blocks so that the crystallization proceeded under temperature gradient. An unidentified metastable phase is observed, when heated between Tx1 and Tx2 temperatures. The BaOB_2O_3 phase is identified in specimens heated above Tx2 temperature. A near (100)[010] preferred orientation is found in the ribbon-like imens by an X-ray diffraction method using pinhole camera. X-ray pole figures of the button-like specimen show a near [101] preferred orientation of columnar crystals observed by optical microscope to have grown parallel to the temperature gradinet. This preliminary srudy has demonstrated that the controlled crystallization of amorphous materials is promising as a method to produce polycrystalline but anisotropic ceramics.

研究了控制陶瓷材料晶体织构的方法。分别采用单辊淬火和两个永久模具之间压制的熔融35mol%BaO-47mol%B_2O_3-18mol%Fe_2O_3和37mol%BaO-40mol%B_2O_3-23mol%Fe_2O_3氧化物通过快速凝固制成薄带状和1 mm厚纽扣状试样。通过 X 射线分析检查样品，并通过 DTA 方法测定结晶温度（Tx1 和 Tx2）。带状试样在均匀加热的炉中结晶，而纽扣状试样则夹在冷热金属块之间，在温度梯度下进行结晶。当在 Tx1 和 Tx2 温度之间加热时，观察到未识别的亚稳态相。在加热到 Tx2 温度以上的样品中发现了 BaOB_2O_3 相。通过使用针孔相机的 X 射线衍射方法，在带状区域中发现了接近 (100)[010] 的择优取向。纽扣状样品的 X 射线极图显示，通过光学显微镜观察到，柱状晶体具有接近 [101] 的择优取向，平行于温度梯度生长。这项初步研究表明，非晶材料的受控结晶是一种很有前景的生产多晶但各向异性陶瓷的方法。