CAPACITANCE MONITORING OF THE INFILTRATION OF CERAMIC PARTICULATE PREFORMS WITH LIQUID-METALS AT 750 TO 850-DEGREES-C

The authors previously developed a capacitance technique to determine the position of the infiltration front as a function of time during th e pressure infiltration of ceramic particulate preforms with liquid me tals. In the present work, the technique was extended to higher temper atures and was used to monitor the infiltration of alumina particulate preforms with Al-Mg alloys and silicon carbide particulate preforms w ith Sn and an Al-Si alloy. The infiltration front position could be de termined in the alumina preforms. However, it was not possible to clea rly interpret the results obtained from the infiltration of semiconduc ting silicon carbide preforms. The observed range of capacitance circu it voltage to infiltration distance ratios agreed with the predicted r ange for both simulated and alumina preform infiltration experiments. Formation of unstable infiltration fronts could also be detected.