알루미나-유리 복합체의 제조에 이용되는 유리의 조성에서 ZrO₂의 함량변화가 복합체의 기계적 성질에 미치는 영향 = Effect of ZrO₂Addition in Glass Composition on the Mechanical Properties of Alumina-Glass Composites

다국어 초록 (Multilingual Abstract)

This study was performed to investigate the effect of ZrO2 addition in borosilicate glasses on the mechanical properties of alumina-glass composites. Porous alumina compacts were prepared by slip casing and sintered at 1100℃ for 2 hours. Dense composites were made by infiltration of molten glass into partially sintered alumina at 1200℃ for 6 hours. Specimens were polished sequentially from #800 to #2000 diamond disk, and the final surface finishing on the tensile side was received an additional polishing sequence through 0.3㎛ diamond paste. Biaxial flexure test was conducted by using ball-on-three-ball method at a crosshead speed of 0.5 mm/min. Fracture toughness was measured by a single edge V-notched beam (SEVNB) method with 2.5×5×20 mm rectangular bar. To examine the microstructural aspect of crack propagation in the alumina-glass composites, Vickers-produced indentation crack was made on the tensile surface at a load of 49.0 N and dwell time of 15 sec, and the radial crack patterns were examined by an optical microscope and a scanning electron microscope.

The results obtained were summarized as follows:
1. The minimum biaxial flexure strength was obtained with an addition of 2 mol% ZrO₂ in glass composition and strength values increased with the increase of ZrO₂ content.
2. The minimum fracture toughness was obtained with an addition of 2 mol% ZrO₂ in glass composition and toughness values decreased with the increase of ZrO₂ content.
3. Fracture surfaces indicated the frictional interlocking of rough surfaces left behind the fracture front.