Preparation of AlN Composites by Infiltration
Date Issued
2010
Date
2010
Author(s)
Yu Chou, Chun
Abstract
The infiltration of copper into AlN powder compact is investigated in the present study. The oxide/sulfide interphase is introduced into both AlN green body and copper matrix with the help of co-existed calcium sulphate. The interphase and inclusions are determined by using XRD technique; the composition by EPMA analysis. The possible role of yttrium in the system is evaluated by using a model system composing of 50% Y2O3 and 50% AlN. The possible interphases are Cu2S, Cu1.8S or other copper-sulfide compounds. The reaction phases, copper alumina oxide and copper alumina sulfide are also observed. By increasing the infiltration temperature, more reaction phases are formed at the interphase between AlN and copper. The gas produced by firing calcium sulfate is different in various atmospheres. More oxygen is formed by firing calcium sulfate in an atmosphere composing of 5%H2/95%N2. On the other hand, less sulfur (or sulfur dioxide) is generated by firing calcium sulfate in 5%H2/95%N2. The distribution of oxygen and sulfur is uniform as the 5%H2/95%N2 atmosphere is used. The thermal conductivity of the infiltrated specimens is lower than the theoretical predictions due to their low density. Nevertheless, the thermal conductivity values are close to the theoretical values by assuming that the specimens are fully dense. This may imply that the thermal resistance of interphases is low.
Subjects
AlN
Copper
Oxidation/Sulfuration
Infiltration
Thermal conductivity
Type
thesis
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