Pressureless joining of SiC ceramics with magnesia-alumina-silica glass ceramics |
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Authors: | Rohit Malik Eui-Hyoun Ryu Young-Wook Kim |
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Affiliation: | Department of Materials Science and Engineering, Functional Ceramics Laboratory, The University of Seoul, Seoul, Republic of Korea |
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Abstract: | Liquid phase sintered SiC ceramics were joined using magnesia-alumina-silica (MAS) glass-ceramic fillers without applied pressure. Four different filler compositions with 9.3–25.2 wt.% MgO, 20.7–33.6 wt.% Al2O3, and 49.2–68.1 wt.% SiO2 were studied. The effects of filler composition and joining temperature (1450–1600°C) on the joint strength were investigated. All compositions exhibited an optimum joining temperature at which the maximum joint strength was obtained. A low joining temperature resulted in poor wetting of the SiC substrate due to the high viscosity of the filler. Whereas a high joining temperature caused dewetting and large unfilled sections in the interlayer due to the deleterious interfacial reactions. The joint strength was inversely proportional to the interlayer thickness, which was a function of filler composition and joining temperature. The SiC ceramic joined at 1525°C with MgO-25 wt.% Al2O3-60 wt.% SiO2 filler exhibited a four-point bending strength of 286 ± 40 MPa. |
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Keywords: | glass-ceramics joints/joining MgO-Al2O3-SiO2 filler silicon carbide |
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