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

1988 Fiscal Year Final Research Report Summary

• Project/Area Number: 61550523
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 金属材料(含表面処理・腐食防食)
• Research Institution: The University of Tokyo
• Principal Investigator: SEKI Fumie Faculty of Engineering Tokyo University Associate Researcher, 工学部, 助手 (20114572)
• Co-Investigator(Kenkyū-buntansha): ITO Kunio Faculty of Engineering Tokyo University Associate Professor, 工学部, 助教授 (20010803)
• Project Period (FY): 1986 – 1987
• Keywords: Amorphous oxide / Preferred orientation / Crystallization / Crystallographic texture

Research Abstract

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.