Spontaneous Infiltration of Alumina by Copper-Oxygen Alloys

Infiltration of alumina powder compacts by molten copper‐oxygen alloys under controlled oxygen partial pressures has been studied. Spontaneous infiltration occurred for copper alloys containing more than approximately 5 at.% oxygen. Despite supersaturation of the copper with oxygen, no Cu2O or interfacial reaction layers of CuAlO2 were resolved by TEM, suggesting the critical wettability for infiltration is not determined by interfacial chemical reaction. CuAlO2 did form, but as discrete inclusions up to 0.5 mm in diameter. Infiltration and microstructure development are discussed in terms of the observed wetting behavior and available data on interfacial oxygen adsorption.