Dense, Shaped Ceramic/Metal Composites at lessthan equal to1000°C by the Displacive Compensation of Porosity (DCP) Method

Abstract

The Displacive Compensation of Porosity method for fabricating dense, shaped ceramic/metal composites at modest temperatures is demonstrated. In this process, liquid‐metal/solid‐ceramic displacement reactions are used to generate more ceramic (by volume) than is consumed, so that pores within a ceramic preform can be filled with the new ceramic phase (i.e., densification without sintering). Dense, lightweight MgO/Mg‐Al composites (74–86 vol% oxide) and higher‐melting, co‐continuous MgAl 2 O 4 /Fe‐Ni‐Al‐bearing composites (42–59 vol% oxide) have been produced via the pressureless infiltration and reaction of magnesium‐bearing liquids with porous preforms of Al 2 O 3 and NiAl 2 O 4 +Fe, respectively, at temperatures of 900°−1000°C. The composites are relatively tough and retain the shapes and dimensions (to within a few percent) of the starting preforms.