Abstract: Described herein are coatings. The coatings can, for example, catalyze carbon gasification. In some examples, the coatings comprise: a first region having a first thickness, the first region comprising manganese oxide, a chromium-manganese oxide, or a combination thereof, and CaWO4, Ba3Y2WO9, or a combination thereof; a second region having a second thickness, the second region comprising X6W6Z, XWZ, or a combination thereof, wherein X is independently Ni or a mixture of Ni and one or more transition metals and Z is independently Si, C, or a combination thereof. In some examples, the coatings further comprise a rare earth element, a rare earth oxide, or a combination thereof.

Abstract: Described herein are coatings. The coatings can, for example, catalyze carbon gasification. In some examples, the coatings comprise: a first region having a first thickness, the first region comprising manganese oxide, a chromium-manganese oxide, or a combination thereof, and CaWO4, Ba3Y2WO9, or a combination thereof; a second region having a second thickness, the second region comprising X6W6Z, XWZ, or a combination thereof, wherein X is independently Ni or a mixture of Ni and one or more transition metals and Z is independently Si, C, or a combination thereof. In some examples, the coatings further comprise a rare earth element, a rare earth oxide, or a combination thereof.

Abstract: This disclosure describes a coating composition comprising: MnxOy, MnCr2O4, or combinations thereof in a first region of a coating having a first thickness, wherein x and y are integers between 1 and 7; and X6W6(Siz, C1-z) in a second region of the coating having a second thickness, wherein X is Ni or a mixture of Ni and one or more transition metals and z ranges from 0 to 1.

Abstract: This disclosure describes a coating composition comprising: MnxOy, MnCr2O4, or combinations thereof in a first region of a coating having a first thickness, wherein x and y are integers between 1 and 7; and X6W6(Siz, C1-z) in a second region of the coating having a second thickness, wherein X is Ni or a mixture of Ni and one or more transition metals and z ranges from 0 to 1.

Abstract: This disclosure describes a coating composition comprising: MnxOy, MnCr2O4, or combinations thereof in a first region of a coating having a first thickness, wherein x and y are integers between 1 and 7; and X6W6(Siz, C1-z) in a second region of the coating having a second thickness, wherein X is Ni or a mixture of Ni and one or more transition metals and z ranges from 0 to 1.

Abstract: This disclosure describes a coating composition comprising: MnxOy, MnCr2O4, or combinations thereof in a first region of a coating having a first thickness, wherein x and y are integers between 1 and 7; and X6W6(Siz, C1-z) in a second region of the coating having a second thickness, wherein X is Ni or a mixture of Ni and one or more transition metals and z ranges from 0 to 1.

Abstract: A stainless steel comprising at least 20 weight % of chromium and at least 1.0 weight % of manganese is adapted to support an overcoating having a thickness from 1 to 10 microns of a spinel of the formula MnxCr3?xO4 wherein x is from 0.5 to 2. Preferably the overcoating is on chromia and has stability against chemical reaction at temperatures at least 25° C. higher than the uncoated chromia.

Abstract: A thermal cracking process using tubes, pipes, and coils made of. An outermost surface covering not less than 55% of stainless steel, said surface having a thickness from 0.1 to 15 microns and being a spinel of the formula MnxCr3-xO4 wherein x is from 0.5 to 2 is not prone to coking and is suitable for hydrocarbyl reactions such as furnace tubes for cracking.

Abstract: A composite surface having a thickness from 10 to 5,000 microns comprising a spinel of the formula MnxCr3?xO4 wherein x is from 0.5 to 2 and oxides of Mn, Si selected from the group consisting of MnO, MnSiO3, Mn2SiO4 and mixtures thereof which are not prone to coking and are suitable for hydrocarbyl reactions such as furnace tubes for cracking.

Abstract: A composite surface having a thickness from 10 to 5,000 microns comprising a spinel of the formula MnxCr3-xO4 wherein x is from 0.5 to 2 and oxides of Mn, Si selected from the group consisting of MnO, MnSiO3, Mn2SiO4 and mixtures thereof which are not prone to coking and are suitable for hydrocarbyl reactions such as furnace tubes for cracking.

Abstract: An outermost surface covering not less than 55% of stainless steel, said surface having a thickness from 0.1 to 15 microns and being a spinel of the formula MnxCr3-xO4 wherein x is from 0.5 to 2 is not prone to coking and is suitable for hydrocarbyl reactions such as furnace tubes for cracking.

Abstract: There is provided a surface alloyed component which comprises a base alloy with a diffusion barrier layer enriched in silicon and chromium being provided adjacent thereto. An enrichment pool layer is created adjacent the diffusion barrier and contains silicon and chromium and optionally titanium or aluminum. The method comprises depositing a surface alloy on the base alloy at a temperature in the range of 400 to 1000° C. and heat treating the surface alloy at a ramp temperature rate of at least 5C°/minute, preferably 10 to 20° C./minute, to a desired maximum temperature at which the surface alloyed component is maintained for a time sufficient to provide the enrichment pool or the enrichment pool with a diffusion barrier layer. A reactive gas treatment may be used to generate a replenishable protective oxide scale of alumina or chromia on the outermost surface of the surface alloyed component.

Abstract: There is provided a surface alloyed component which comprises a base alloy with a diffusion barrier layer enriched in silicon and chromium being provided adjacent thereto. An enrichment pool layer is created adjacent the diffusion barrier and contains silicon and chromium and optionally titanium or aluminum. The method comprises depositing a surface alloy on the base alloy at a temperature in the range of 400 to 1000° C. and heat treating the surface alloy at a ramp temperature rate of at least 5C°/minute, preferably 10 to 20° C./minute, to a desired maximum temperature at which the surface alloyed component is maintained for a time sufficient to provide the enrichment pool or the enrichment pool with a diffusion barrier layer. A reactive gas treatment may be used to generate a replenishable protective oxide scale of alumina or chromia on the outermost surface of the surface alloyed component.

Abstract: There is provided a surface alloyed component which comprises a base alloy with a diffusion barrier layer enriched in silicon and chromium being provided adjacent thereto. An enrichment pool layer is created adjacent said diffusion barrier and contains silicon and chromium and optionally titanium or aluminum. A reactive gas treatment may be used to generate a replenishable protective scale on the outermost surface of said component.

Abstract: There is provided a surface alloyed component which comprises a base alloy with a diffusion barrier layer enriched in silicon and chromium being provided adjacent thereto. An enrichment pool layer is created adjacent said diffusion barrier and contains silicon and chromium and optionally titanium or aluminum. A reactive gas treatment may be used to generate a replenishable protective scale on the outermost surface of said component.