Influence of Oxygen Partial Pressure on the Physical Properties of Chromium Alumina Cermets

The signficance of the equilibrium oxygen pressure for the formation of chromium sesquioxide in sintering is extended to other oxide systems containing chronium. In chromium-alumina cermets the influence of the sintering oxygen pressure on the ambient flexural strength, Young's modulus, fracture behavior measured by Kic factor, and thermal shock behavior is shown. The strength dependence begins ather the equilibrium is exceeded. The maximum strength is nearly 40% higher within a decade above the equilibrium oxygen partial pressure. The fracture toughness has shown an inverse relationship with oxygen partial pressure. The mechanical behavior is interpreted from the microstructure in terms of the degree and type of oxidation of the chromium particles an its effects on the interfacial strength.