Creation of Ceramic Composites by High Temperature Oxidation of Iron and Nickel Alloys Using Oxidative Constructing Approach

Resumo

High temperature oxidation of iron and nickel alloy blanks is characterized by the formation of bilayer ceramic and cermet structures, holding the original shape of the metal blank. The composition of the resulting ceramic depends on the temperature and synthesis time and the ratio of components with different sensitivity to oxygen in the initial alloy. Dwell at a low temperature leads to stabilization of the composition of the synthesized ceramic within the outer layer owing to the concentration leveling of the spinel phase. The outer and inner layers are characterized by different morphology of the chip surface and different porosity. The inner polycrystalline layer is porous; the outer layer of the sample is monolithic. The structure of interphase boundaries of the heterophasic sample ensures the integrity of the material and provides high adhesion properties of different phases to each other. The resulting oxidative constructed composites of ferrous alloys with nickel are promising for testing as inert anodes.