Phase Transformation and Densification Behavior of Microwave-Sintered Si3N4–Y2O3–MgO–ZrO2 System |
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Authors: | Sreekumar Chockalingam David A Earl Vasantha R W Amarakoon |
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Affiliation: | New York State College of Ceramics at Alfred University, Alfred, New York 14802 |
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Abstract: | A 2.45 GHz microwave-sintered Si3N4–Y2O3–MgO system containing various amounts of ZrO2 secondary additives have been studied with respect to phase transformation and densification behavior. The temperature dependent dielectric properties were measured from 25°C to 1400°C using a conventional cavity perturbation technique. Phase transformation behavior was studied using X-ray diffractometry. Microwave sintered results were compared with those of conventional sintered results. It has been found that α to β phase transformation was completed at a lower temperature in microwave-sintered samples than those of the conventionally sintered samples. Density of the microwave-sintered samples increased up to 2.5 wt% of ZrO2 addition and thereafter it showed a tendency to decrease or remain constant. The decrease in density is attributed to the pore generation caused by decomposition due to the localized over heating. |
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