발간논문

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This study has been carried out. to investigate the reaction effect of synthetic Ca-P-O and Ba-P-O system through the TG-DTA and X-ray diffraction analysis with respect to Fe-Si alloy addition, Fe₂O₃, Cr₂O₃, CaCl₂and BaCl₂respectively. The result obtained from the experiments are as follows ; 1. Fe₂O₃added samples were showed exothermic reaction while Cr₂O₃added samples were showed endothermic reaction during the TG-DTA at 1100-1200℃ 2. And CaCl₂and BaCl₂compounds, too, have reacted endothermally. 3. The products of muffle furnace reactions from the Ca-P-O system were found to be Ca₂P₂O_7, Ca₂Fe(Po₄)₂, CaCrO₄, CaFe₂O_7, etc, and from Ba-P-O system were composed of Ba₃(PO₄)₂, BaSiO₄, BaFe₂O₄and Ba(PO₃)₂, etc. 4. Therefore, synthetic phosphate system of Ca and Ba, added with Fe₂O₃, formed Ca-Fe-Si-O compound and Ba-Fe-Si-O compound, respectively, and the system added with Cr₂O₃was exceedingly easy to form the Ba₃(PO₄)₂.

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Interfacial reaction during thermal exposure of the Al₂O₃/Al-alloy monofilament composites has been investigated in relation to tensile properties of the composites. In the case of the Al₂O₃/pure-Al composites, reaction products such as Al₂O₃and Si were formed at interfaces due to reaction between SiO₂in the fiber and Al matrix at 600℃, while the interfacial reaction did not occur at 500℃. In the case of the Al₂O₃/7075-alloy composites, reaction products such as MgO, Al₂O₃and Si began to form at 500℃, and they became remarkably coarse at 600℃. Tensile strength and the Weibull moduli of the thermally exposed composites decreased with the progress of interfacial reaction. Tensile strength and the Wibull moduli of the Al₂O₃/pure-al composites were much higher than those of the Al₂O₃/7475-alloy composites, respectively, when they were exposed at 600℃.

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