Abstract: The present invention relates to a method for manufacturing a metal-oxide-based ceramic, including, in order, the step of inserting, into a flash sintering device, a nanocrystalline powder comprising crystallites and crystallite agglomerates of a ceramic of formula, Zr1-xMxO2, where M is chosen from yttrium, scandium and cerium, or Ce1-xM?xO2, where M? is chosen from gadolinium, scandium, samarium and yttrium, where x lies between 0 and 0.2, the powder having an average crystallite size of between 5 and 50 nm, an average crystallite agglomerate size of between 0.5 and 20 ?m, and a specific surface area of between 20 and 100 m2/g. The invention further includes the step of flash sintering the powder by applying a pressure of between 50 and 150 MPa, at a temperature of between 850° C. and 1400° C., for a time of between 5 and 30 minutes.

Abstract: The present invention relates to a method for manufacturing a metal-oxide-based ceramic, including, in order, the step of inserting, into a flash sintering device, a nanocrystalline powder comprising crystallites and crystallite agglomerates of a ceramic of formula, Zr1-xMxO2, where M is chosen from yttrium, scandium and cerium, or Ce1-xM?xO2, where M? is chosen from gadolinium, scandium, samarium and yttrium, where x lies between 0 and 0.2, the powder having an average crystallite size of between 5 and 50 nm, an average crystallite agglomerate size of between 0.5 and 20 ?m, and a specific surface area of between 20 and 100 m2/g. The invention further includes the step of flash sintering the powder by applying a pressure of between 50 and 150 MPa, at a temperature of between 850° C. and 1400° C., for a time of between 5 and 30 minutes.

Abstract: A method is disclosed for producing a protective coating on a chromium oxide-forming substrate, which comprises the steps of: (a) applying on the chromium-oxide-forming substrate having at least one alloying addition selected from the group consisting of manganese, magnesium, and vanadium, a coating consisting essentially of at least one spinel-forming element selected from the group consisting of cobalt, nickel, copper and vanadium, (b) forming a chromium oxide layer at the substrate/applied coating interface, and (c) at a temperature of 500° C. to 1000° C. causing the diffusion of the at least one alloying addition through the chromium oxide layer and forming a compound thereof with the at least one spinel-forming element diffusing from the applied coating and forming between the chromium oxide layer on the substrate and the applied coating, a uniform, compact, adherent chromium-free gas-tight spinel layer.

Abstract: A method is disclosed for producing a protective coating on a chromium oxide forming substrate, in which on a surface of the chromium oxide forming substrate, a mixture of CoO, MnO, and CuO in suspension is applied, or a powdered CoO, MnO, and CuO is applied to said surface; at a temperature of 500 to 1000° C., to form a protective coating on the chromium oxide forming substrate, said protective coating consisting essentially of a uniform, gas-tight, compact, adherent chromium free spinel layer on which is coated a metal oxide layer of CoO, MnO, and CuO. Also disclosed are interconnectors for high temperature fuel cells as the chromium oxide forming substrates on which the protective coating is applied.

Abstract: As a rule, chromium-oxide forming materials for high temperatures, in particular chromium-based alloys or chromium-rich alloys based on iron (ferritic steel), are used as interconnector materials that are subjected to high temperatures. At SOFC operating temperatures, said material group forms a chromium-based oxidic top coating, which has the advantage of preventing rapid oxidation damage, but also the disadvantage of continuing to react, forming Cr(VI) compounds. Said volatile compounds react regularly with the cathode material, producing the negative effect of impairing the oxygen reduction. The invention relates to a method for producing a gas-tight protective coating, devoid of chromium, for chromium-oxide forming substrates, such as for example typical interconnector materials, said coating regularly preventing the evaporation of chromium VI compounds during SOFC operating conditions. The protective coating has the general formula: Co3-x-yCuxMnyO4, in which 0<x<1.5, 0<y<3 and (x+y)<3.

Abstract: As a rule, chromium-oxide forming materials for high temperatures, in particular chromium-based alloys or chromium-rich alloys based on iron (ferritic steel), are used as interconnector materials that are subjected to high temperatures. At SOFC operating temperatures, said material group forms a chromium-based oxidic top coating, which has the advantage of preventing rapid oxidation damage, but also the disadvantage of continuing to react, forming Cr(VI) compounds. Said volatile compounds react regularly with the cathode material, producing the negative effect of impairing the oxygen reduction. The invention relates to a gas-tight protective coating, devoid of chromium, for chromium-oxide forming substrates, such as for example typical interconnector materials, said coating regularly preventing the evaporation of chromium VI compounds during SOFC operating conditions. The invention also relates to a simple method for producing said gas-tight protective coating that is devoid of chromium.